WO2021243512A1

WO2021243512A1 - Beam failure recovery response optimization

Info

Publication number: WO2021243512A1
Application number: PCT/CN2020/093732
Authority: WO
Inventors: Nan Zhang; Yongjun XU; Long HAN
Original assignee: Qualcomm Incorporated
Priority date: 2020-06-01
Filing date: 2020-06-01
Publication date: 2021-12-09

Abstract

Wireless communication systems and methods related to beam failure recovery are provided. A user equipment (UE) stores, at a memory of the UE, a record of a plurality of transmit-receive beam pair selections in one or more cells and associated cell information. The UE detects a beam failure. The UE performs, in response to the beam failure, a beam failure recovery according to the stored record.

Description

BEAM FAILURE RECOVERY RESPONSE OPTIMIZATION

Nan Zhang, Yongjun Xu, Long Han

TECHNICAL FIELD

The technology described below relates generally to wireless communication systems, and more particularly to beam failure recovery operations a wireless communication network.

INTRODUCTION

Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power) . A wireless multiple-access communications system may include a number of base stations (BSs) , each simultaneously supporting communications for multiple communication devices, which may be otherwise known as user equipment (UE) .

To meet the growing demands for expanded mobile broadband connectivity, wireless communication technologies are advancing from the long term evolution (LTE) technology to a next generation new radio (NR) technology, which may be referred to as 5 ^th Generation (5G) . For example, NR is designed to provide a lower latency, a higher bandwidth or a higher throughput, and a higher reliability than LTE. NR is designed to operate over a wide array of spectrum bands, for example, from low-frequency bands below about 1 gigahertz (GHz) and mid-frequency bands from about 1 GHz to about 6 GHz, to high-frequency bands such as millimeter wave (mmWave) bands. NR is also designed to operate across different spectrum types, from licensed spectrum to unlicensed and shared spectrum. Spectrum sharing enables operators to opportunistically aggregate spectrums to dynamically support high-bandwidth services. Spectrum sharing can extend the benefit of NR technologies to operating entities that may not have access to a licensed spectrum.

While high frequency bands, such as mmWave bands, can provide a higher data throughput than lower frequency bands, the path-loss can be high. To overcome the high path-loss, BSs and UEs may use beamforming to form directional beams for communications.

BRIEF SUMMARY OF SOME EXAMPLES

The following summarizes some aspects of the present disclosure to provide a basic understanding of the discussed technology. This summary is not an extensive overview of all contemplated features of the disclosure and is intended neither to identify key or critical elements of all aspects of the disclosure nor to delineate the scope of any or all aspects of the disclosure. Its sole purpose is to present some concepts of one or more aspects of the disclosure in summary form as a prelude to the more detailed description that is presented later.

For example, in an aspect of the disclosure, a method of wireless communication performed by a user equipment (UE) , the method includes storing, at a memory of the UE, a record of a plurality of transmit-receive beam pair selections in one or more cells and associated cell information; detecting a beam failure; and performing, in response to the beam failure, a beam failure recovery according to the stored record.

In an additional aspect of the disclosure, a user equipment (UE) includes a memory; and a processor configured to store, at the memory, a record of a plurality of transmit-receive beam pair selections in one or more cells and associated cell information; detect a beam failure; and perform, in response to the beam failure, a beam failure recovery according to the stored record.

In an additional aspect of the disclosure, a non-transitory computer-readable medium having program code recorded thereon, the program code includes code for causing a user equipment (UE) to store, at a memory of the UE, a record of a plurality of transmit-receive beam pair selections in one or more cells and associated cell information; code for causing the UE to detect a beam failure; and code for causing the UE to perform, in response to the beam failure, a beam failure recovery according to the stored record.

In an additional aspect of the disclosure, a user equipment (UE) includes means for storing, at a memory of the UE, a record of a plurality of transmit-receive beam pair selections in one or more cells and associated cell information; means for detecting a beam failure; and means for performing, in response to the beam failure, a beam failure recovery according to the stored record.

Other aspects, features, and embodiments of the present invention will become apparent to those of ordinary skill in the art, upon reviewing the following description of specific, exemplary embodiments of the present invention in conjunction with the accompanying figures. While features of the present invention may be discussed relative to certain embodiments and figures below, all embodiments of the present invention can include one or more of the advantageous features discussed herein. In other words, while one or more embodiments may be discussed as having certain advantageous features, one or more of such features may also be used in accordance with the various embodiments of the invention discussed herein. In similar fashion, while exemplary embodiments may be discussed below as device, system, or method embodiments it should be understood that such exemplary embodiments can be implemented in various devices, systems, and methods.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a wireless communication network according to some aspects of the present disclosure.

FIG. 2A illustrates a wireless communication network utilizing directional beams for communications according to some aspects of the present disclosure.

FIG. 2B is a timing diagram illustrating a transmit-receive beam pair candidate identification according to some aspects of the present disclosure.

FIG. 3 is a signaling diagram illustrating a transmit-receive beam pair selection scheme according to some aspects of the present disclosure.

FIG. 4 is a signaling diagram illustrating a transmit-receive beam pair record generation method according to some aspects of the present disclosure.

FIG. 5 illustrates an exemplary transmit-receive beam pair selection record storage scheme according to some aspects of the present disclosure.

FIG. 6 is a signaling diagram illustrating a beam failure recovery method according to some aspects of the present disclosure.

FIG. 7 is a block diagram of an exemplary base station (BS) according to some aspects of the present disclosure.

FIG. 8 is a block diagram of an exemplary user equipment (UE) according to some aspects of the present disclosure.

FIG. 9 is a flow diagram of a wireless communication method according to some aspects of the present disclosure.

DETAILED DESCRIPTION

The detailed description set forth below, in connection with the appended drawings, is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of the various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. In some instances, well-known structures and components are shown in block diagram form in order to avoid obscuring such concepts.

This disclosure relates generally to wireless communications systems, also referred to as wireless communications networks. In various embodiments, the techniques and apparatus may be used for wireless communication networks such as code division multiple access (CDMA) networks, time division multiple access (TDMA) networks, frequency division multiple access (FDMA) networks, orthogonal FDMA (OFDMA) networks, single-carrier FDMA (SC-FDMA) networks, LTE networks, Global System for Mobile Communications (GSM) networks, 5 ^th Generation (5G) or new radio (NR) networks, as well as other communications networks. As described herein, the terms “networks” and “systems” may be used interchangeably.

An OFDMA network may implement a radio technology such as evolved UTRA (E-UTRA) , Institute of Electrical and Electronics Engineers (IEEE) 802.11, IEEE 802.16, IEEE 802.20, flash-OFDM and the like. UTRA, E-UTRA, and GSM are part of universal mobile telecommunication system (UMTS) . In particular, long term evolution (LTE) is a release of UMTS that uses E-UTRA. UTRA, E-UTRA, GSM, UMTS and LTE are described in documents provided from an organization named “3rd Generation Partnership Project” (3GPP) , and cdma2000 is described in documents from an organization named “3rd Generation Partnership Project 2” (3GPP2) . These various radio technologies and standards are known or are being developed. For example, the 3rd Generation Partnership Project (3GPP) is a collaboration between groups of telecommunications associations that aims to define a globally applicable third generation (3G) mobile phone specification. 3GPP long term evolution (LTE) is a 3GPP project which was aimed at improving the UMTS mobile phone standard. The 3GPP may define specifications for the next generation of mobile networks, mobile systems, and mobile devices. The present disclosure is concerned with the evolution of wireless technologies from LTE, 4G, 5G, NR, and beyond with shared access to wireless spectrum between networks using a collection of new and different radio access technologies or radio air interfaces.

In particular, 5G networks contemplate diverse deployments, diverse spectrum, and diverse services and devices that may be implemented using an OFDM-based unified, air interface. In order to achieve these goals, further enhancements to LTE and LTE-A are considered in addition to development of the new radio technology for 5G NR networks. The 5G NR will be capable of scaling to provide coverage (1) to a massive Internet of things (IoTs) with a ultra-high density (e.g., ～1M nodes/km ²) , ultra-low complexity (e.g., ～10s of bits/sec) , ultra-low energy (e.g., ～10+ years of battery life) , and deep coverage with the capability to reach challenging locations; (2) including mission-critical control with strong security to safeguard sensitive personal, financial, or classified information, ultra-high reliability (e.g., ～99.9999%reliability) , ultra-low latency (e.g., ～ 1 ms) , and users with wide ranges of mobility or lack thereof; and (3) with enhanced mobile broadband including extreme high capacity (e.g., ～ 10 Tbps/km ²) , extreme data rates (e.g., multi-Gbps rate, 100+ Mbps user experienced rates) , and deep awareness with advanced discovery and optimizations.

A 5G NR communication system may be implemented to use optimized OFDM-based waveforms with scalable numerology and transmission time interval (TTI) . Additional features may also include having a common, flexible framework to efficiently multiplex services and features with a dynamic, low-latency time division duplex (TDD) /frequency division duplex (FDD) design; and with advanced wireless technologies, such as massive multiple input, multiple output (MIMO) , robust millimeter wave (mmWave) transmissions, advanced channel coding, and device-centric mobility. Scalability of the numerology in 5G NR, with scaling of subcarrier spacing, may efficiently address operating diverse services across diverse spectrum and diverse deployments. For example, in various outdoor and macro coverage deployments of less than 3GHz FDD/TDD implementations, subcarrier spacing may occur with 15 kHz, for example over 5, 10, 20 MHz, and the like bandwidth (BW) . For other various outdoor and small cell coverage deployments of TDD greater than 3 GHz, subcarrier spacing may occur with 30 kHz over 80/100 MHz BW. For other various indoor wideband implementations, using a TDD over the unlicensed portion of the 5 GHz band, the subcarrier spacing may occur with 60 kHz over a 160 MHz BW. Finally, for various deployments transmitting with mmWave components at a TDD of 28 GHz, subcarrier spacing may occur with 120 kHz over a 500 MHz BW.

The scalable numerology of the 5G NR facilitates scalable TTI for diverse latency and quality of service (QoS) requirements. For example, shorter TTI may be used for low latency and high reliability, while longer TTI may be used for higher spectral efficiency. The efficient multiplexing of long and short TTIs to allow transmissions to start on symbol boundaries. 5G NR also contemplates a self-contained integrated subframe design with UL/downlink scheduling information, data, and acknowledgement in the same subframe. The self-contained integrated subframe supports communications in unlicensed or contention-based shared spectrum, adaptive UL/downlink that may be flexibly configured on a per-cell basis to dynamically switch between UL and downlink to meet the current traffic needs.

Various other aspects and features of the disclosure are further described below. It should be apparent that the teachings herein may be embodied in a wide variety of forms and that any specific structure, function, or both being disclosed herein is merely representative and not limiting. Based on the teachings herein one of an ordinary level of skill in the art should appreciate that an aspect disclosed herein may be implemented independently of any other aspects and that two or more of these aspects may be combined in various ways. For example, an apparatus may be implemented or a method may be practiced using any number of the aspects set forth herein. In addition, such an apparatus may be implemented or such a method may be practiced using other structure, functionality, or structure and functionality in addition to or other than one or more of the aspects set forth herein. For example, a method may be implemented as part of a system, device, apparatus, and/or as instructions stored on a computer readable medium for execution on a processor or computer. Furthermore, an aspect may comprise at least one element of a claim.

A wireless communication network may operate over a high frequency band, such as a mmWave band, to provision for a high data throughput. To overcome the high path-loss in the high frequency band, a base station (BS) may transmit reference signals and/or synchronization signal blocks (SSBs) in different beam directions, for example, by sweeping across a set of predefined transmit beam characteristics (e.g., transmit beam directions) . The BS may repeat the transmissions of the reference signals and/or SSBs in the different transmit beam characteristics or beam directions to allow a user equipment (UE) to perform signal measurements and beam selection. The UE may also sweep across a set of predefined receive beam characteristics (e.g., receive beam directions) to determine signal measurements for the reference signals and/or SSBs at the different transmit beam characteristics or beam directions. In some instances, the UE may report the measurements to the BS. The BS and the UE may together determine the best transmit-receive beam pair (e.g., a transmit beam characteristic or beam direction at the BS and a receive beam characteristic or beam direction at the UE) for subsequent communications. In some instances, the UE may determine the best transmit-receive beam pair for communications or at least the best transmit beam characteristic of the BS for communicating with the BS and request the BS to utilize the determined transmit beam characteristic to communicate with the UE.

In an example, the BS may sweep across a set of 4 transmit beam directions for SSB transmissions and the UE may sweep across a set of 3 receive beam directions for receiving a signal from the BS. Thus, there are 12 combinations (e.g., 4×3 = 12) of transmit-receive beam pair measurements that the BS and/or the UE may select for communications with each other. In some aspects, the BS may transmit an SSB at intervals of about 20 milliseconds (ms) and sweep across the different beam directions for the SSB transmissions. As such, it may take the UE at least about 240 ms (e.g., 20×12 = 240) to collect signal measurements for all 12 combinations before the UE may determine a best transmit-receive beam pair. The measurement duration may increase as the number of transmit beam directions at the BS increases and/or as the number of receive beam directions at the UE increases.

A long measurement duration may not be of a great concern during initial beam discovery. However, a long measurement duration can be problematic during a beam failure recovery. For instance, the channel condition may degrade and/or the UE may move out of a coverage of a currently selected beam, and thus the UE may detect a radio link failure, which may be referred to as a beam failure. Upon detecting a beam failure, the UE may perform a beam failure recovery procedure where the UE may perform beam measurement and beam reselection (with the BS sweeping across the various transmit beam directions and the UE sweeping across the various receive beam directions) . During the beam measurements, the BS and the UE may not communicate data with each other. In other words, an ongoing communication between the BS and the UE prior to the beam failure may be interrupted (e.g., fail and/or delayed) .

The beam failure recovery response time can be critical for ultra-reliable low-latency communication (URLLC) , which may have a stringent latency (e.g., about 1 ms or less) and reliability (e.g., 1e-6 error rate) . Accordingly, it may be desirable to reduce the beam failure recovery response time.

The present application describes mechanisms for a UE to reduce beam failure recovery response time. For example, the UE may record and store or cache a plurality of transmit-receive beam pair selections in one or more frequently visited cells and associated cell information in a memory at the UE. Upon detecting a beam failure event, the UE may perform a beam failure recovery procedure by utilizing the stored transmit-receive beam pair selections without having to perform an extensive receive beam sweep at the UE and/or wait for the BS to sweep across the various transmit beams. For instance, the UE may select a first transmit-receive beam pair selection from the plurality of transmit-receive beam pair selections in the record, for example, based on cell information and/or movement information associated with the UE. The UE may perform a beam measurement based on the selected first transmit-receive beam pair selection. If the selected transmit-receive beam pair provides a sufficient signal quality (e.g., satisfying a certain signal threshold) , the UE may utilize the selected transmit-receive beam pair to continue with the beam failure recovery procedure.

In some aspects, the UE may select the first transmit-receive beam pair selection from the plurality of transmit-receive beam pair selections in the stored record based on cell information (e.g., a cell identifier (ID) and/or a public land mobile network (PLMN) information) associated with the cell where the beam failure is detected and cell information associated with the first transmit-receive beam pair selection. In some aspects, the UE may select the first transmit-receive beam pair selection from the plurality of transmit-receive beam pair selection in the stored record based on position information (e.g., a geographical location or an orientation of the UE) of the UE when the beam failure is detected and position information associated with the first transmit-receive beam pair selection. In some aspects, the UE may select the first transmit-receive beam pair selection from the plurality of transmit-receive beam pair selection based on the first transmit-receive beam pair selection being the most popular selection or with the highest preference among a subset of transmit-receive beam pair selections in the cell where the beam failure is detected.

In some aspects, the UE may update the record when the UE determines a new transmit-receive beam pair (e.g., a final transmit-receive beam pair selection) for a beam failure recovery in a frequently visited cell. In some aspects, the UE may update the record when the UE travelled a certain distance in a frequently visited cell. In some aspects, the UE may update the record when the UE performs a cell re-selection in a frequently visited cell. In some aspects, the UE may update the record based on a certain update cycle or schedule (e.g., every 24 hours, every week, or every month) .

Aspects of the present disclosure can provide several benefits. For example, storing or caching of transmit-receive beam pair selections for a cell frequently visited by the UE can allow the UE to quickly select a transmit-receive beam pair from the record when a beam failure occurs in the cell, reducing or eliminating the most time-consuming task of transmit-receive beam pair candidate identification in a beam failure recovery procedure. Associating cell information and/or position information with the transmit-receive beam pair selection allows the UE to select a most suitable transmit-receive beam pair from the record for beam failure recovery. Selecting a most popular or a most preferred transmit-receive beam pair selection from the record may increase the chance of the UE in successfully completing the beam failure recovery. Updating the record based on a distance travelled by the UE in a frequently visited cell allows the UE to build a record of transmit-receive beam pair selections for different areas within the cell. Updating the record based on an update cycle allows the UE to keep the transmit-receive beam pair selections in the record current.

FIG. 1 illustrates a wireless communication network 100 according to some aspects of the present disclosure. The network 100 may be a 5G network. The network 100 includes a number of base stations (BSs) 105 (individually labeled as 105a, 105b, 105c, 105d, 105e, and 105f) and other network entities. A BS 105 may be a station that communicates with UEs 115 and may also be referred to as an evolved node B (eNB) , a next generation eNB (gNB) , an access point, and the like. Each BS 105 may provide communication coverage for a particular geographic area. In 3GPP, the term “cell” can refer to this particular geographic coverage area of a BS 105 and/or a BS subsystem serving the coverage area, depending on the context in which the term is used.

A BS 105 may provide communication coverage for a macro cell or a small cell, such as a pico cell or a femto cell, and/or other types of cell. A macro cell generally covers a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscriptions with the network provider. A small cell, such as a pico cell, would generally cover a relatively smaller geographic area and may allow unrestricted access by UEs with service subscriptions with the network provider. A small cell, such as a femto cell, would also generally cover a relatively small geographic area (e.g., a home) and, in addition to unrestricted access, may also provide restricted access by UEs having an association with the femto cell (e.g., UEs in a closed subscriber group (CSG) , UEs for users in the home, and the like) . A BS for a macro cell may be referred to as a macro BS. A BS for a small cell may be referred to as a small cell BS, a pico BS, a femto BS or a home BS. In the example shown in FIG. 1, the

BSs

105d and 105e may be regular macro BSs, while the BSs 105a-105c may be macro BSs enabled with one of three dimension (3D) , full dimension (FD) , or massive MIMO. The BSs 105a-105c may take advantage of their higher dimension MIMO capabilities to exploit 3D beamforming in both elevation and azimuth beamforming to increase coverage and capacity. The BS 105f may be a small cell BS which may be a home node or portable access point. A BS 105 may support one or multiple (e.g., two, three, four, and the like) cells.

The network 100 may support synchronous or asynchronous operation. For synchronous operation, the BSs may have similar frame timing, and transmissions from different BSs may be approximately aligned in time. For asynchronous operation, the BSs may have different frame timing, and transmissions from different BSs may not be aligned in time.

The UEs 115 are dispersed throughout the wireless network 100, and each UE 115 may be stationary or mobile. A UE 115 may also be referred to as a terminal, a mobile station, a subscriber unit, a station, or the like. A UE 115 may be a cellular phone, a personal digital assistant (PDA) , a wireless modem, a wireless communication device, a handheld device, a tablet computer, a laptop computer, a cordless phone, a wireless local loop (WLL) station, or the like. In one aspect, a UE 115 may be a device that includes a Universal Integrated Circuit Card (UICC) . In another aspect, a UE may be a device that does not include a UICC. In some aspects, the UEs 115 that do not include UICCs may also be referred to as IoT devices or internet of everything (IoE) devices. The UEs 115a-115d are examples of mobile smart phone-type devices accessing network 100. A UE 115 may also be a machine specifically configured for connected communication, including machine type communication (MTC) , enhanced MTC (eMTC) , narrowband IoT (NB-IoT) and the like. The UEs 115e-115h are examples of various machines configured for communication that access the network 100. The UEs 115i-115k are examples of vehicles equipped with wireless communication devices configured for communication that access the network 100. A UE 115 may be able to communicate with any type of the BSs, whether macro BS, small cell, or the like. In FIG. 1, a lightning bolt (e.g., communication links) indicates wireless transmissions between a UE 115 and a serving BS 105, which is a BS designated to serve the UE 115 on the downlink (DL) and/or uplink (UL) , desired transmission between BSs 105, backhaul transmissions between BSs, or sidelink transmissions between UEs 115.

In operation, the BSs 105a-105c may serve the

UEs

115a and 115b using 3D beamforming and coordinated spatial techniques, such as coordinated multipoint (CoMP) or multi-connectivity. The macro BS 105d may perform backhaul communications with the BSs 105a-105c, as well as small cell, the BS 105f. The macro BS 105d may also transmits multicast services which are subscribed to and received by the

UEs

115c and 115d. Such multicast services may include mobile television or stream video, or may include other services for providing community information, such as weather emergencies or alerts, such as Amber alerts or gray alerts.

The BSs 105 may also communicate with a core network. The core network may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. At least some of the BSs 105 (e.g., which may be an example of a gNB or an access node controller (ANC) ) may interface with the core network through backhaul links (e.g., NG-C, NG-U, etc. ) and may perform radio configuration and scheduling for communication with the UEs 115. In various examples, the BSs 105 may communicate, either directly or indirectly (e.g., through core network) , with each other over backhaul links (e.g., X1, X2, etc. ) , which may be wired or wireless communication links.

The network 100 may also support mission critical communications with ultra-reliable and redundant links for mission critical devices, such as the UE 115e, which may be a drone. Redundant communication links with the UE 115e may include links from the

macro BSs

105d and 105e, as well as links from the small cell BS 105f. Other machine type devices, such as the UE 115f (e.g., a thermometer) , the UE 115g (e.g., smart meter) , and UE 115h (e.g., wearable device) may communicate through the network 100 either directly with BSs, such as the small cell BS 105f, and the macro BS 105e, or in multi-step-size configurations by communicating with another user device which relays its information to the network, such as the UE 115f communicating temperature measurement information to the smart meter, the UE 115g, which is then reported to the network through the small cell BS 105f. The network 100 may also provide additional network efficiency through dynamic, low-latency TDD/FDD communications, such asV2V, V2X, C-V2X communications between a

UE

115i, 115j, or 115k and other UEs 115, and/or vehicle-to-infrastructure (V2I) communications between a

UE

115i, 115j, or 115k and a BS 105.

In some implementations, the network 100 utilizes OFDM-based waveforms for communications. An OFDM-based system may partition the system BW into multiple (K) orthogonal subcarriers, which are also commonly referred to as subcarriers, tones, bins, or the like. Each subcarrier may be modulated with data. In some instances, the subcarrier spacing between adjacent subcarriers may be fixed, and the total number of subcarriers (K) may be dependent on the system BW. The system BW may also be partitioned into subbands. In other instances, the subcarrier spacing and/or the duration of TTIs may be scalable.

In some aspects, the BSs 105 can assign or schedule transmission resources (e.g., in the form of time-frequency resource blocks (RB) ) for downlink (DL) and uplink (UL) transmissions in the network 100. DL refers to the transmission direction from a BS 105 to a UE 115, whereas UL refers to the transmission direction from a UE 115 to a BS 105. The communication can be in the form of radio frames. A radio frame may be divided into a plurality of subframes or slots, for example, about 10. Each slot may be further divided into mini-slots. In a FDD mode, simultaneous UL and DL transmissions may occur in different frequency bands. For example, each subframe includes a UL subframe in a UL frequency band and a DL subframe in a DL frequency band. In a TDD mode, UL and DL transmissions occur at different time periods using the same frequency band. For example, a subset of the subframes (e.g., DL subframes) in a radio frame may be used for DL transmissions and another subset of the subframes (e.g., UL subframes) in the radio frame may be used for UL transmissions.

The DL subframes and the UL subframes can be further divided into several regions. For example, each DL or UL subframe may have pre-defined regions for transmissions of reference signals, control information, and data. Reference signals are predetermined signals that facilitate the communications between the BSs 105 and the UEs 115. For example, a reference signal can have a particular pilot pattern or structure, where pilot tones may span across an operational BW or frequency band, each positioned at a pre-defined time and a pre-defined frequency. For example, a BS 105 may transmit cell specific reference signals (CRSs) and/or channel state information –reference signals (CSI-RSs) to enable a UE 115 to estimate a DL channel. Similarly, a UE 115 may transmit sounding reference signals (SRSs) to enable a BS 105 to estimate a UL channel. Control information may include resource assignments and protocol controls. Data may include protocol data and/or operational data. In some aspects, the BSs 105 and the UEs 115 may communicate using self-contained subframes. A self-contained subframe may include a portion for DL communication and a portion for UL communication. A self-contained subframe can be DL-centric or UL-centric. A DL-centric subframe may include a longer duration for DL communication than for UL communication. A UL-centric subframe may include a longer duration for UL communication than for UL communication.

In some aspects, the network 100 may be an NR network deployed over a licensed spectrum. The BSs 105 can transmit synchronization signals (e.g., including a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) ) in the network 100 to facilitate synchronization. The BSs 105 can broadcast system information associated with the network 100 (e.g., including a master information block (MIB) , remaining system information (RMSI) , and other system information (OSI) ) to facilitate initial network access. In some instances, the BSs 105 may broadcast the PSS, the SSS, and/or the MIB in the form of synchronization signal block (SSBs) over a physical broadcast channel (PBCH) and may broadcast the RMSI and/or the OSI over a physical downlink shared channel (PDSCH) .

In some aspects, a UE 115 attempting to access the network 100 may perform an initial cell search by detecting a PSS from a BS 105. The PSS may enable synchronization of period timing and may indicate a physical layer identity value. The UE 115 may then receive a SSS. The SSS may enable radio frame synchronization, and may provide a cell identity value, which may be combined with the physical layer identity value to identify the cell. The PSS and the SSS may be located in a central portion of a carrier or any suitable frequencies within the carrier.

After receiving the PSS and SSS, the UE 115 may receive a MIB. The MIB may include system information for initial network access and scheduling information for RMSI and/or OSI. After decoding the MIB, the UE 115 may receive RMSI and/or OSI. The RMSI and/or OSI may include radio resource control (RRC) information related to random access channel (RACH) procedures, paging, control resource set (CORESET) for physical downlink control channel (PDCCH) monitoring, physical UL control channel (PUCCH) , physical UL shared channel (PUSCH) , power control, and SRS.

After obtaining the MIB, the RMSI and/or the OSI, the UE 115 can perform a random access procedure to establish a connection with the BS 105. In some examples, the random access procedure may be a four-step random access procedure. For example, the UE 115 may transmit a random access preamble and the BS 105 may respond with a random access response. The random access response (RAR) may include a detected random access preamble identifier (ID) corresponding to the random access preamble, timing advance (TA) information, a UL grant, a temporary cell-radio network temporary identifier (C-RNTI) , and/or a backoff indicator. Upon receiving the random access response, the UE 115 may transmit a connection request to the BS 105 and the BS 105 may respond with a connection response. The connection response may indicate a contention resolution. In some examples, the random access preamble, the RAR, the connection request, and the connection response can be referred to as message 1 (MSG1) , message 2 (MSG2) , message 3 (MSG3) , and message 4 (MSG4) , respectively. In some examples, the random access procedure may be a two-step random access procedure, where the UE 115 may transmit a random access preamble and a connection request in a single transmission and the BS 105 may respond by transmitting a random access response and a connection response in a single transmission.

After establishing a connection, the UE 115 and the BS 105 can enter a normal operation stage, where operational data may be exchanged. For example, the BS 105 may schedule the UE 115 for UL and/or DL communications. The BS 105 may transmit UL and/or DL scheduling grants to the UE 115 via a PDCCH. The scheduling grants may be transmitted in the form of DL control information (DCI) . The BS 105 may transmit a DL communication signal (e.g., carrying data) to the UE 115 via a PDSCH according to a DL scheduling grant. The UE 115 may transmit a UL communication signal to the BS 105 via a PUSCH and/or PUCCH according to a UL scheduling grant.

In some aspects, the BS 105 may communicate with a UE 115 using HARQ techniques to improve communication reliability, for example, to provide a URLLC service. The BS 105 may schedule a UE 115 for a PDSCH communication by transmitting a DL grant in a PDCCH. The BS 105 may transmit a DL data packet to the UE 115 according to the schedule in the PDSCH. The DL data packet may be transmitted in the form of a transport block (TB) . If the UE 115 receives the DL data packet successfully, the UE 115 may transmit a HARQ ACK to the BS 105. Conversely, if the UE 115 fails to receive the DL transmission successfully, the UE 115 may transmit a HARQ NACK to the BS 105. Upon receiving a HARQ NACK from the UE 115, the BS 105 may retransmit the DL data packet to the UE 115. The retransmission may include the same coded version of DL data as the initial transmission. Alternatively, the retransmission may include a different coded version of the DL data than the initial transmission. The UE 115 may apply soft-combining to combine the encoded data received from the initial transmission and the retransmission for decoding. The BS 105 and the UE 115 may also apply HARQ for UL communications using substantially similar mechanisms as the DL HARQ.

In some aspects, the network 100 may operate over a system BW or a component carrier (CC) BW. The network 100 may partition the system BW into multiple BWPs (e.g., portions) . A BS 105 may dynamically assign a UE 115 to operate over a certain BWP (e.g., a certain portion of the system BW) . The assigned BWP may be referred to as the active BWP. The UE 115 may monitor the active BWP for signaling information from the BS 105. The BS 105 may schedule the UE 115 for UL or DL communications in the active BWP. In some aspects, a BS 105 may assign a pair of BWPs within the CC to a UE 115 for UL and DL communications. For example, the BWP pair may include one BWP for UL communications and one BWP for DL communications.

In some aspects, the network 100 may operate over a shared channel, which may include shared frequency bands or unlicensed frequency bands. For example, the network 100 may be an NR-unlicensed (NR-U) network operating over an unlicensed frequency band. In such an aspect, the BSs 105 and the UEs 115 may be operated by multiple network operating entities. To avoid collisions, the BSs 105 and the UEs 115 may employ an LBT procedure to monitor for transmission opportunities (TXOPs) in the shared channel. A wireless communication device may perform an LBT in the shared channel. LBT is a channel access scheme that may be used in the unlicensed spectrum. When the LBT results in an LBT pass (the wireless communication device wins contention for the wireless medium) , the wireless communication device may access the shared medium to transmit and/or receive data. For example, a transmitting node (e.g., a BS 105 or a UE 115) may perform an LBT prior to transmitting in the channel. When the LBT passes, the transmitting node may proceed with the transmission. When the LBT fails, the transmitting node may refrain from transmitting in the channel. In an example, the LBT may be based on energy detection. For example, the LBT results in a pass when signal energy measured from the channel is below a threshold. Conversely, the LBT results in a failure when signal energy measured from the channel exceeds the threshold. In another example, the LBT may be based on signal detection. For example, the LBT results in a pass when a channel reservation signal (e.g., a predetermined preamble signal) is not detected in the channel. Conversely, the LBT results in a failure when a channel reservation signal is detected in the channel. A TXOP may also be referred to as channel occupancy time (COT) .

In some aspects, the network 100 may operate over a high frequency band, for example, in a frequency range 1 (FR1) band or a frequency range 2 (FR2) band. FR1 may refer to frequencies in the sub-6 GHz range and FR2 may refer to frequencies in the mmWave range. To overcome the high path-loss at high frequency, the BSs 105 and the UEs 115 may communicate with each other using directional beams, for example, by performing analog and/or digital beamforming. For instance, a BS 105 may transmit SSBs by sweeping across a set of predefined transmit beam characteristics (e.g. transmit beam directions) and may repeat the SSB transmissions at a certain time interval in the set of beam directions to allow a UE 115 to perform initial network access. In some instances, each beam and its corresponding characteristics may be identified by a beam index. For instance, each SSB may include an indication of a beam index corresponding to the beam used for the SSB transmission. The UE 115 may determine signal measurements, such as reference signal received power (RSRP) and/or reference signal received quality (RSRQ) , for the SSBs at the different beam directions and select a best DL beam. The UE 115 may indicate the selection by transmitting a PRACH signal (e.g., MSG1) using PRACH resources associated with the selected beam direction. For instance, the SSB transmitted in a particular beam direction may indicate PRACH resources that may be used by a UE 115 to communicate with the BS 105 in that particular beam direction. After selecting the best DL beam, the UE 115 may complete the random access procedure (e.g., the 4-step random access or the 2-step random access) and proceed with network registration and normal operation data exchange with the BS 105. In some aspects, the UE 115 may also sweep across a set of predefined receive beam characteristics (e.g., receive beam directions) during SSB measurements to determine a best receive beam (e.g., receive beam characteristic) for communicating with the BS 105.

In some instances, the channel condition may degrade and/or the UE 115 may move out of a coverage of a currently selected beam, and thus the UE 115 may detect a radio link failure, which may be referred to as a beam failure. Upon detecting a beam failure, the UE 115 may perform a beam failure recovery procedure with the BS 105. To perform beam failure recovery, the UE 115 may perform a beam measurement and beam re-selection (with the BS 105 sweeping across the various transmit beam directions and the UE 115 sweeping across the various receive beam directions) .

In some aspects, to reduce beam recovery response time, the UE 115 may record transmit-receive beam pair selections for one or more cells that are frequently visited by the UE 115. The UE 115 may store the transmit-receive beam pair selections at a memory (e.g., the memory 804 of FIG. 8) of the UE 115. The UE 115 may also store cell information and/or position information associated with the transmit-receive beam pair selections along with the transmit-receive beam pair selections. In some aspects, each transmit-receive beam pair selection may include a transmit beam characteristic (e.g., transmit beam direction) of a BS 105 in a corresponding cell and a receive beam characteristic (e.g., receive beam direction) of the UE 115. Upon detecting a beam failure, the UE 115 may select a transmit-receive beam pair selection from the stored transmit-receive beam pair selections. The UE 115 may utilize the selected transmit-receive beam pair selection for beam failure recovery instead of waiting for the BS 105 to sweep across various transmit beam directions and sweeping across all the receive beam directions at the UE 115 for signal measurements to identify a best transmit-receive beam pair for beam failure recovery. In other words, the time for identifying transmit-receive beam pair candidates can be significantly reduced. Mechanisms for performing beam failure recovery with an optimized or reduced response time are described in greater detail herein.

FIG. 2A illustrates a wireless communication network 200 utilizing directional beams for communications according to some aspects of the present disclosure. The network 200 may correspond to a portion of the network 100. Although FIG. 2A illustrates one BS 105 and one UE 115, it should be understood that in other examples the network 200 may include any suitable number of BSs 105 (e.g., 2, 3, 4, 5, or more) and any suitable number of UEs 115 (2, 3, 4, 5, 6, 7 or more) . In the network 200, the BS 105 may communicate with the UE 115 over a high-frequency band, such as a sub-6 GHz band or a mmWave band. The BS 105 and/or the UE 115 may apply beamforming (e.g., analog beamforming and/or precoding) to generate directional beams for communications.

In the illustrated example of FIG. 2A, the BS 105 may generate a set of transmit

beams

210, 212, 214, and 216 for communications with the UE 115. The set of transmit

beams

210, 212, 214, and 216 can be predefined. Although FIG. 2A illustrates the BS 105 utilizing four transmit beams, it should be understood that in other examples, the BS 105 may use any suitable number of transmit beams (e.g., 2, 3, 8, 10, 12, 16, 32, 64 or more) . Each of the BS 105’s transmit

beams

210, 212, 214, and 216 may have a certain transmit beam characteristic (e.g., beam direction and/or beam width) . For example, the transmit

beams

210, 212, 214, and 216 may have different beam directions as shown. Additionally or alternatively, the transmit

beams

210, 212, 214, and 216 may have different beam widths. The BS 105 may transmit beam reference signals by sweeping across the set of transmit

beams

210, 212, 214, and 216 (shown in FIG. 2B below) . In some aspects, the beam reference signals may include be SSBs and/or channel state information-reference signals (CSI-RSs) .

To communicate with the BS 105, the UE 115 may also generate a set of receive

beams

220, 222, and 224. The set of transmit

beams

220, 222, and 224 can be predefined. Although FIG. 2A illustrates the UE 115 utilizing three receive beams, it should be understood that in other examples, the UE 115 may use any suitable number of transmit beams (e.g., 2, 4 or more) . Each of the UE 115’s receive

beams

220, 222, and 224 may have a certain receive beam characteristic (e.g., beam direction and/or beam width) . For example, the receive

beams

220, 222, and 224 may have different beam directions as shown. Additionally or alternatively, the receive

beams

220, 222, and 224 may have different beam widths. The UE 115 may monitor for signals from the BS 105 by sweeping across the set of receive

beams

220, 222, and 224 (shown in FIG. 2B below) . The UE 115 may determine signal measurements using the different receive

beams

220, 222, and 224 for each of the BS 105’s transmit

beams

210, 212, 214, and 216. In some instances, the UE 115 may report the signal measurements to the BS 105. The UE 115 and the BS 105 may determine a pair of transmit beam and receive beam that may provide the best receive quality (e.g., highest RSRQ or RSRP) for the UE 115.

FIG. 2B is discussed in relation to FIG. 2A to illustrate transmit beam sweeping at a BS 105 and receive beam sweeping at a UE 115 for beam pair candidate identification, for example, during an initial network access and/or a beam failure recovery. FIG. 2B is a timing diagram illustrating a beam measurement scheme 230 according to some aspects of the present disclosure. The scheme 230 may be employed by a BS such as the BS 105 and a UE such as the UE 115 in a network such as the network 100 for communications. In FIG. 2B, the x-axis represents time in some arbitrary units.

As shown, the BS 105 may transmit beam reference signals 232 by sweeping across the set of transmit

beams

210, 212, 214, and/or 216. Thus, each beam reference signal 232 may have a certain transmit beam characteristic of the BS 105. In some aspects, each beam reference signal 232 may include an SSB. Each SSB transmitted by the BS 105 using a certain transmit

beam

210, 212, 214, or 216 may be identified by an SSB beam index. For instance, an SSB transmitted by the BS 105 using the transmit beam 210 may have a beam index of 0, an SSB transmitted by the BS 105 using the transmit beam 212 may have a beam index of 1, an SSB transmitted by the BS 105 using the transmit beam 214 may have a beam index of 2, and an SSB transmitted by the BS 105 using the transmit beam 216 may have a beam index of 3.

In some aspects, the BS 105 may repeat the transmission of the beam reference signal 232 at time intervals 202 to sweep through each of the transmit

beams

210, 212, 214, and 216. As shown, the BS 105 transmits a beam reference signal 232 using the transmit beam 210 at a first time interval 202, switches to transmit a beam reference signal 232 using the transmit beam 212 at a second time interval 202, and so on. The BS 105 may repeat the sweeping across the set of transmit

beams

210, 212, 214, and 216 at time intervals 204 (shown as 204 _(n) and 204 _(n+1) ) . In an example, the beam reference signals 232 may correspond to SSBs with a cycle time or periodicity of about 20ms, and thus the time interval 204 may be about 80 ms with four transmit

beams

210, 212, 214, and 216.

The UE 115 may monitor for a beam reference signal 232 from the BS 105 by sweeping across the set of receive

beams

220, 222, and 224. For instance, during the time interval 204 _(n) , the UE 115 may configure its transceiver (e.g., the transceiver 810 of FIG. 8) and/or antennas (e.g., the antennas 816 of FIG. 8) to receive signals using the receive beam 220. In other words, the UE 115 may receive signals based on receive beam characteristics (e.g., beam direction) of the receive beam 220. Upon detecting a reference signal 232, the UE 115 may determine a signal measurement (e.g., RSRQ or RSRP) for the detected reference signal 232. For example, by the end of the time interval 204 _(n) , the UE 115 may have determined a signal measurement for each of the transmit

beams

210, 212, 214, and 216 based on the receive beam characteristic of the receive beam 220.

In some instances, the UE 115 may be aware of the schedule for the beam reference signals 232. For example, the UE 115 may configure its transceiver and/or antennas to switch to a next receive beam 222 at a next time interval 204 _(n+1) and repeat the monitoring and/or signal measurements for the reference signals 232 transmitted with the transmit

beams

210, 212, 214, and 216. The UE 115 may further configure its transceiver and/or antennas to switch to the receive beam 224 at a subsequent time interval 204 _(n+2) and repeat the monitoring and/or signal measurements for the reference signals 232 transmitted with the transmit

beams

210, 212, 214, and 216. At the end of the time interval 204 _(n+2) , the UE 115 may have signal measurements for all 12 combinations (e.g., 4×3=12) of transmit-receive beam pairs. The UE 115 may select a transmit-receive beam pair having a highest signal measurement for subsequent communications with the BS 105.

FIG. 3 is a signaling diagram illustrating a transmit-receive beam pair selection method 300 according to some aspects of the present disclosure. The method 300 may be implemented between a BS 105 and a UE 115 in the network 100. The BS 105 may correspond to the BS 105 shown in FIGS. 2A and 2B configured to transmit signal using a set of transmit beam characteristics (e.g., the

beams

210, 212, 214, and 216) . The UE 115 may correspond to the UE 115 shown in FIGS. 2A and 2B configured to receive signals using a set of receive beam characteristics (e.g., the

beams

220, 222, and 224) . Although the method 300 illustrates the BS 105 in communications with one UE 115, it should be understood that in other examples the BS 105 may communicate with any suitable number of UEs 115 (e.g., about 2, 9, 4, 5, 6 or more) . The method 300 may employ similar mechanisms as discussed above with reference to FIGS. 2A and 2B. As illustrated, the method 300 includes a number of enumerated actions, but embodiments of the method 300 may include additional actions before, after, and in between the enumerated actions. In some embodiments, one or more of the enumerated actions may be omitted or performed in a different order.

At action 305, the BS 105 transmits a first reference signal based on a first transmit beam characteristic. The first reference signal may include an SSB with beam index 0. For instance, the BS 105 may generate a beam (e.g., the transmit beam 220) having the first transmit beam characteristic and transmit the first reference signal using the beam.

At action 310, the UE 115 determines a first signal measurement for the first reference signal based on a first receive beam characteristic. For instance, the UE 115 may configure its transceiver (e.g., the transceiver 810 of FIG. 8) and/or antennas (e.g., the antennas 816 of FIG. 8) to receive the first reference signal using a beam (e.g., the receive beam 220) having the first receive beam characteristic. The first signal measurement may be a RSRQ or an L1-RSRP measuerment.

At action 315, the BS 105 transmits a second reference signal (e.g., SSB with beam index 1) based on a second transmit beam characteristic (e.g., using the transmit beam 212) .

At action 320, the UE 115 determines a second signal measurement (e.g., RSRQ or L1-RSRP) for the second reference signal based on the first receive beam characteristic.

At action 325, the BS 105 transmits a third reference signal (e.g., SSB with beam index 0) based on the first transmit beam characteristic

At action 330, the UE 115 determines a third signal measurement (e.g., RSRQ or L1-RSRP) for the third reference signal based on a second receive beam characteristic (e.g., using the receive beam 222) .

At action 335, the BS 105 transmits a fourth reference signal (e.g., SSB with beam index 1) based on the second transmit beam characteristic.

At action 340, the UE 115 determines a fourth signal measurement (e.g., RSRQ or L1-RSRP) for the fourth reference signal based on the second receive beam characteristic.

At action 345, the UE 115 determines a best transmit-receive beam pair based on the first, second, third, and fourth signal measurements. For instance, the UE 115 may select the third signal measurement from the first, second, third, and fourth signal measurements based on the third signal measurement having a highest value among the first, second, third, and fourth signal measurements and satisfying a signal threshold. Since the third signal measurement is measured from the third reference signal having the first transmit beam characteristic of the BS 105 based on the second receive beam characteristic of the UE 115, the UE 115 may subsequently communicate with the BS 105 based on the first transmit beam characteristic of the BS 105 and the second receive beam characteristic of the UE 115.

In some aspects, the UE 115 may implement the method 300 during an initial beam discovery phase, for example, for initial network access. In some aspects, the UE 115 may implement the method 300 during a beam failure recovery. As discussed above, the amount of time for beam measurements may increase as the number of the transmit beam characteristics or beam directions at the BS 105 increases and/or as the number of receive beam characteristics or beam directions at the UE 115 increases. Referring to the example discussed above with reference to FIGS. 2A and 2B where the BS 105 transmits a beam reference signal 232 at intervals of 20 ms and sweeps through four transmit

beams

210, 212, 214, and 216 for the transmissions and the UE 115 sweeps through three receive

beams

220, 222, and 224 for measurements, it will take the UE 115 about 240 ms to cycle through all the 12 combinations of transmit-receive beam pairs and identify a best transmit-receive beam pair before the UE 115 may transmit a beam failure recovery request to the BS 105 to indicate a desired transmit beam characteristic (from the best transmit-receive beam pair) . In general, transmit-receive beam pair candidate identification may consume up to about 80 percent (%) of the beam failure recovery time. The long transmit-receive beam pair candidate identification time may not be desirable for URLLC.

Accordingly, the present disclosure provides techniques for a UE to reduce beam failure recovery response time. For example, the UE may record and cache potential transmit-receive beam pair selections in one or more frequently visited cells as will be discussed more fully in relation to FIGS. 4 and 5 below. Upon detecting a beam failure event, the UE may perform a beam failure recovery procedure by utilizing the cached transmit-receive beam pair selections as will be discussed more fully below in relation to FIG. 6.

FIG. 4 is a flow diagram of a transmit-receive beam pair record generation method 400 according to some aspects of the present disclosure. Aspects of the method 400 can be executed by a computing device (e.g., a processor, processing circuit, and/or other suitable component) of a wireless communication device or other suitable means for performing the steps. For example, a wireless communication device, such as a UE 115 or a UE 800, may utilize one or more components, such as the processor 802, the memory 804, the sensor module 807, the beam module 808, the communication module 809, the transceiver 810, the modem 812, and/or the one or more antennas 816, to execute the steps of method 400. The method 400 may employ similar mechanisms as described above in FIGS. 2A, 2B, and 3. As illustrated, the method 400 includes a number of enumerated steps, but aspects of the method 400 may include additional steps before, after, and in between the enumerated steps. In some aspects, one or more of the enumerated steps may be omitted or performed in a different order.

In the method 400, a UE 115 may generate a record of transmit-receive beam pair selections in one or more frequently visited cells (e.g., about 1, 2, or 3) . For instance, the UE 115 may move around within a user’s house and/or home garden. A cell may cover a substantially large region or area. Thus, even if the UE moves from the user’s house to the garden, the UE may still be within the same serving cell. Additionally, transmit-receive beam pairs between the UE 115 and a BS 105 in the serving cell may be relatively stable over a long period of time. A transmit-receive beam pair between the UE 115 and the BS 105 may refer to the pairing of a receive beam characteristic of the UE 115 and a transmit beam characteristic of the BS 105 as discussed above in relation to FIGS. 2A-3B and FIG. 3. In some instances, the signal quality for a certain transmit-receive beam pair between the UE 115 and the BS 105 may provide about the same average signal quality (e.g., average RSRP or average RSRQ) for a long period of time. For example, the average signal quality for a certain transmit-receive beam pair between the UE 115 and the BS 105 may remain above the same for a duration of a day, a month, or a year. As such, the UE 115 can record and store potential transmit-receive beam pairs in the cell and associated cell information and/or position information of the UE 115 in a memory (e.g., the memory 804 of FIG. 8) and utilize the stored transmit-receive beam pairs at a later time for beam failure recovery upon detecting a beam failure event.

For instance, at block 405, the UE 115 determines a first transmit-receive beam pair selection in a first cell. In some aspects, the UE 115 may determine the first transmit-receive beam pair selection by employing the method 300. For example, the BS 105 may transmit beam reference signals (e.g., SSBs) by sweeping across a set of transmit beam characteristics of the BS 105. The UE 115 may determine signals measurements for the reference signals by sweeping across a set of receive beam characteristics of the UE 115. For example, the UE 115 may determine a signal measurement for each transmit-receive beam pair (e.g., a transmit beam characteristic of the BS 105 and a receive beam characteristic of the UE) . As an example, the UE 115 may determine that a first transmit beam characteristic of the BS 105 and a first receive beam characteristic of the UE 115 provide a best signal quality (e.g., highest RSRP or highest RSRQ) among a plurality of transmit-receive beam pairs in the first cell. The UE 115 may further determine that the signal quality provided by the first transmit beam characteristic of the BS 105 and the first receive beam characteristic of the UE 115 satisfies a certain signal threshold.

At block 410, the UE 115 generates a record by adding the first transmit-receive beam pair selection.

At block 415, the UE 115 identifies cell information associated with the first cell. For example, the cell information may include a cell ID identifying the first cell and/or PLMN information associated with the first cell. PLMN information may include a PLMN ID, which may include a mobile country code (MCC) and a mobile network code (MNC) . In some aspects, the UE 115 may identify the cell information and/or the PLMN information from system information (e.g., SSBs) broadcast by the BS 105.

At block 420, the UE 115 determines first position information associated with the UE 115, for example, at the time when the first transmit-receive beam pair selection is determined. The first position information may include geographical location information and/or orientation information associated with the UE 115. The geographical location information may include a geographical coordinate identifying a location of the UE 115. The orientation information may include rotation and/or translation information of the UE 115 with respect to a reference coordinate system in space. The UE 115 may be equipped with sensors and may determine the first position information based on sensing data received from the sensors. The sensors may include various types of sensors, for example, including radar, lidar, and/or a global positioning system (GPS) .

At block 425, the UE 115 stores the record and associated cell information and first position information in a memory at the UE 115. An example of a cached record and associated cell and/or first position information are shown in FIG. 5 and discussed in greater detail below.

At block 430, the UE 115 determines whether a condition for determining another transmit-receive beam pair selection is triggered. The condition can be related to a beam failure in the first cell. For example, the UE 115 may move from one location within the first cell to another location within the first cell. Additionally or alternatively, an orientation of the UE 115 may have changed. For example, a user of the UE 115 may hold the UE 115 at a different orientation. Additionally or alternatively, the channel may degrade due to inference. If the UE 115 determines that the condition is not triggered, the UE 115 may wait for the condition to be triggered. However, if the UE 115 determines that the condition is triggered, the UE 115 may proceed to block 435.

At block 435, the UE 115 determines a second transmit-receive beam pair selection, for example, using similar mechanisms at block 405. For example, the second transmit-receive beam pair selection may include a second transmit beam characteristic of the BS 105 and a second receive beam characteristic of the UE 115.

At block 440, the UE 115 adds the second transmit-receive beam pair selection to the record stored in the memory.

At block 445, the UE 115 associates the second transmit-receive beam pair selection with the cell information.

At block 450, the UE 115 determines second position information associated with the UE 115 at the time when the second transmit-receive beam pair selection is determined, for example, using similar mechanisms as at block 420. The second position information may include geographical information and/or orientation information of the UE 115 at the time when the second transmit-receive beam pair selection is determined.

At block 455, the UE 115 stores the second position information in the memory in association with the second transmit-receive beam pair selection. In some instances, if the second position information is the same or similar to the first position information, the UE 115 may associate the second transmit-receive beam pair selection with the first position information without storing the second position information. For instance, the UE 115 may determine that a distance between a geographical location of the UE 115 indicated by the first position information and a geographical location of the UE 115 indicated by the second position information is within a certain distance, the UE 115 may not store the second position information.

Subsequently, the UE 115 may repeat the

blocks

435, 440, 450, 455, and 460 when the condition at block 430 is triggered. For example, the UE 115 may determine a third transmit-receive beam pair selection, a fourth transmit-receive beam pair selection, and so on. Over time, the UE 115 may have a record of multiple transmit-receive beam pairs in the first cell that may provide the UE 115 with a good signal quality (e.g., high SNR, high RSRP, or high RSRQ) for communicating with the BS 105. For example, the first transmit-receive beam pair selection may provide the UE 115 with a good signal quality when the UE 115 is inside the house and the second transmit-receive beam pair selection may provide the UE 115 with a good signal quality when the UE 115 is in the garden, and so on. In some aspects, the UE 115 may add the second transmit-receive beam pair selection to the record if the UE 115 determines that the second transmit-receive beam pair selection is not already in the record. In other words, the UE 115 may add the second transmit-receive beam pair selection based on the second transmit-receive beam pair selection having a different pairing of transmit beam characteristic of the BS 105 and receive beam characteristic of the UE 115 than any other transmit-receive beam pair selection currently in the record.

In some aspects, the UE 115 may associate or assign a transmit-receive beam pair selection in the record with a preference or popularity metric. For example, the first transmit-receive beam pair selection may have a higher preference or more popular than the second transmit-receive beam pair selection. The preference can be based on a signal quality, a frequency of use, and/or a frequency of beam failures for a transmit-receive beam pair selection. For example, the first transmit-receive beam pair selection may have a higher signal quality than the second transmit-receive beam pair selection. Additionally or alternatively, the UE 115 may use the first transmit-receive beam pair selection to communicate with the BS 105 more frequently than the second transmit-receive beam pair selection. Additionally or alternatively, the UE 115 may experience a less number of beam failures when utilizing the first transmit-receive beam pair selection for communicating with the BS 105 than the second transmit-receive beam pair selection. In some aspects, the UE 115 may also categorize the transmit-receive beam pair selections in the record based on a geographical location and/or an orientation of the UE 115. For example, the UE 115 may determine a preference for a transmit-receive beam pair selection within a subset of the transmit-receive beam pair selections in the record associated with about the same geographical location or orientation of the UE 115.

In some aspects, the UE 115 may travel to a second cell different from the first cell, where the second cell may not be a frequently visited cell. Thus, when the UE 115 determines a transmit-receive beam pair selection for the second cell (associated with a different cell ID than the first cell) , the UE may not add the transmit-receive beam pair selection to the record. For instance, the UE 115 may determine a transmit-receive beam pair selection and add the transmit-receive beam pair selection to the record if a cell ID associated with the transmit-receive beam pair selection is the same as a cell ID associated with a transmit-receive beam pair selection in the stored record.

In some aspects, the UE 115 may update the record when a new transmit-receive beam pair (that is not the same as any transmit-receive beam pair currently in the record) is selected for a beam failure recovery, after the UE 115 travelled a certain distance (within a coverage read of the first cell) , or based on an update cycle (e.g., every 24 hours, every week, or every month) . In some aspects, the UE 115 may update the record when the UE 115 performs a cell re-reselection. For example, the UE 115 may perform the cell re-selection while the UE 115 is within an area frequently visited by the UE 115. The cell re-selection can be due to various reasons, for example, a change in network deployment or a change in network operator.

While the method 400 is described in the context of generating a record of transmit-receive beam pair selections for one frequently visited cells, the UE 115 can apply the method 400 to generate a record of transmit-receive beam pair selections for two or more frequently visited cells.

FIG. 5 is discussed in relation to FIG. 4 to illustrate caching or storage of transmit-receive beam pair selection record. FIG. 5 illustrates an exemplary transmit-receive beam pair selection record storage scheme 500 according to some aspects of the present disclosure. The scheme 500 may be employed by a UE such as the UE 115 for storing a record of transmit-receive beam pair selections for one or more cells frequently visited by the UE 115. The scheme 500 can be employed in conjunction with the

method

230, 300, and 400.

In the scheme 500, the UE 115 may store a record of a plurality of transmit-receive beam pair selections and associated cell information and/or position information in a memory for later use during a beam failure recovery. As shown, the UE 115 stores a record 520 including a plurality of transmit-receive beam pair selections (shown as 522 and 524) in a memory 510 of the UE 115. The memory 510 may be a cache memory and may be similar to the memory 804 of FIG. 8. In some instances, the memory 510 may be a non-volatile memory that may hold the record 520 or any saved data even if the UE 115 is powered-off. The transmit-receive

beam pair selections

522 and 524 may be determined as discussed above in the method 400. For instance, the transmit-receive

beam pair selections

522 and 524 may be determined within a first cell frequently visited by the UE 115. The transmit-receive beam pair selection 522 may include a first transmit beam characteristic 530 of the BS 105 and a first receive beam characteristic 532 of the UE 115. The transmit-receive beam pair selection 524 may include a second transmit beam characteristic 534 of the BS 105 and a second receive beam characteristic 536 of the UE 115. For example, the transmit-receive beam pair selection 522 may be determined at block 405 of FIG. 4 and the transmit-receive beam pair selection 524 may be determined at block 435 of FIG. 4.

The UE 115 may also store cell information 540 associated with the transmit-receive

beam pair selections

522 and 524 in the memory 510. The cell information 540 may include a cell ID identifying the first cell and/or PLMN information (e.g., a PLMN ID) associated with the first cell) .

The UE 115 may also store position information associated with the transmit-receive

beam pair selection

522 and 524 in the memory 510. As an example, the transmit-receive beam pair selection 522 may be associated with position information 550 and the transmit-receive beam pair selection 524 may be associated with position information 552. The position information 550 may include geographical location information and/or orientation information associated with the UE 115 at the time when the UE 115 determines the transmit-receive beam pair selection 522. The position information 552 may include geographical location information and/or orientation information associated with the UE 115 at the time when the UE 115 determines the transmit-receive beam pair selection 524. For instance, the UE 115 may be equipped with sensor (s) and may determine the

position information

550 and 552 based on data received from the sensor (s) .

In some aspects, the UE 115 may associate multiple transmit-receive beam pair selections similar to the transmit-receive

beam pair selections

522 and 524 with certain position information similar to the position information 550 and 525. For instance, the transmit-receive beam pair selections may provide the UE 115 with different signal qualities satisfying a signal threshold at about the same location. The UE 115 may assign a preference or popularity metric to the transmit-receive beam pair selections based on signal qualities, frequency of use by the UE 115, and/or frequency of beam failures. The UE 115 may associate each of the transmit-receive beam pair selections with a preference or popularity metric store the transmit-receive beam pair selections in an order of preferences.

In some aspects, the UE 115 may associate the transmit-receive

beam pair selections

522 and 524 with the cell information 540 via pointers and/or soft links (as shown by the solid arrows and dashed arrows) . Similarly, the UE 115 may associate the transmit-receive

beam pair selections

522 and 524 with the

position information

550 and 552, respectively, via pointers and/or soft links. Alternatively, the UE 115 may include cell information and position information for each transmit-receive

beam pair selection

522, 524 in the record 520. In general, the UE 115 may arrange the storage of the transmit-receive

beam pair selections

522 and 524, the cell information 540, and the

position information

550 and 552 in any suitable storage arrangement in the memory 510.

While the scheme 500 is described in the context of storing a record of transmit-receive beam pair selections for one frequently visited cells, the UE 115 can apply the scheme 500 to store a record of transmit-receive beam pair selections for two or more frequently visited cells and may associate each transmit-receive beam pair selection in the record with corresponding cell information.

FIG. 6 is a signaling diagram illustrating a beam failure recovery method 600 according to some aspects of the present disclosure. The method 600 may be implemented between a BS 105 and a UE 115 in the network 100. The BS 105 may correspond to the BS 105 shown in FIGS. 2A and 2B configured to transmit signal using a set of transmit beam characteristics (e.g., the

beams

220, 222, and 224) . Although the method 600 illustrates the BS 105 in communications with one UE 115, it should be understood that in other examples the BS 105 may communicate with any suitable number of UEs 115 (e.g., about 2, 9, 4, 5, 6 or more) . The method 600 may employ similar mechanisms as discussed above with reference to FIGS. 2A-2B, 3, 4, and/or 5. As illustrated, the method 600 includes a number of enumerated actions, but embodiments of the method 600 may include additional actions before, after, and in between the enumerated actions. In some embodiments, one or more of the enumerated actions may be omitted or performed in a different order.

The method 600 may be implemented after the UE 115 has a record (e.g., the record 520) of transmit-receive beam pair selections (e.g., the transmit-receive beam pair selections 522 and 524) for one or more cells frequently visited by the UE 115 stored in a memory (e.g., the memory 510 and/or the memory 804 of FIG. 8) of the UE 115. For example, the UE 115 may employ the method 400 to generate the record of transmit-receive beam pair selections and employ the scheme 500 to store the record and associated cell information (e.g., the cell information 540) and position information (e.g., the position information 550 and 552) of the UE 115 at the memory.

At action 610, the BS 105 and the UE 115 communicates with each other in a first cell, for example, after establishing a connection. In some instances, the communication may be a URLLC. The first cell may be frequently visited by the UE 115. For example, the first cell may be covering a home area or an office area of a user of the UE 115.

At action 620, the UE 115 detects a beam failure. The UE 115 may detect the beam failure in various ways. In an example, the UE 115 may monitor for SSBs from the BS 105 and may determine a beam failure has occurred when the UE 115 failed to receive an SSB according to a schedule or cycle time of the SSB transmissions or detected a signal measurement of an SSB failing to satisfy a signal threshold (e.g., below a threshold) . Additionally or alternatively, the UE 115 may determine a beam failure has occurred when the ongoing communication has a high error rate (e.g., packet error rate) .

At action 630, upon detecting the beam failure, the UE 115 selects a first transmit-receive beam pair selection from the record of transmit-receive beam pair selections for beam failure recovery. The first transmit-receive beam pair selection may include a first transmit beam characteristic of the BS 105 and a first receive beam characteristic of the UE 115. In some aspects, the UE 115 may select the first transmit-receive beam pair selection from the record of transmit-receive beam pair selections based on the first transmit-receive beam pair selection being associated with the first cell. For instance, the UE 115 may compare the cell information associated with the first cell where the beam failure is detected and cell information associated with the first transmit-receive beam pair selection in the record. If the cell information (e.g., a cell ID or a PLMN ID) are the same for the first cell and the first transmit-receive beam pair selection, the UE 115 may select the first transmit-receive beam pair selection.

In some aspects, the UE 115 may select the first transmit-receive beam pair selection from the record of transmit-receive beam pair selections based on position information associated with the UE 115. For instance, the UE 115 may include sensor (s) (e.g., radar, lidar, and/or a GPS) and may receive data or sensor information related to a position of the UE 115. The UE 115 may determine a distance travelled by the UE 115 and/or a geographical location (e.g., a geographical coordinate) based on the data or sensor information received from the sensor (s) . The UE 115 may determine that the UE 115 is still within a coverage area of the first cell based on the travel distance and/or the geographical coordinate information. In some aspects, the UE 115 may select the first based on a comparison of position information (e.g., a geographical location and/or an orientation with respect to a reference coordinate system in space) associated with the UE 115 when the beam failure is detected and position information (e.g., a geographical location and/or an orientation with respect to the reference coordinate system) associated with the first transmit-receive beam pair selection. For instance, the UE 115 may select the first transmit-receive beam pair selection when the position information associated with the UE 115 when the beam failure is detected is similar to the position information associated with the first transmit-receive beam pair selection. For example, the UE 115 may determine that a distance between a geographical location of the UE 115 when the beam failure is detected and a geographical location of the UE 115 associated with the first transmit-receive beam pair selection satisfies a distance threshold. Additionally or alternatively, the UE 115 may determine that a difference (e.g., an angle difference) between a physical orientation of the UE 115 with respect to a reference coordinate system when the beam failure is detected and a physical orientation of the UE 115 associated with the first transmit-receive beam pair selection with respect to a reference coordinate system satisfies a threshold.

In some aspects, the UE 115 may select the first transmit-receive beam pair selection from the record of transmit-receive beam pair selections based on the first transmit-receive beam pair selection having a highest preference among the transmit-receive beam pair selections in the record.

At action 640, the BS 105 transmits a first reference signal (e.g., the reference signal 232, an SSB, or a CSI-RS) based on the first transmit beam characteristic (e.g., using a transmit

beam

210, 212, 214, or 216) .

At action 650, the UE 115 performs a beam measurement directly based on the first transmit-receive beam pair selection. In other words, the UE 115 may configure its transceiver (e.g., the transceiver 810 of FIG. 8) and/or antennas (e.g., the antennas 816 of FIG. 8) to monitor for the first reference signal using the first receive beam characteristic without performing a beam search or beam pair candidate identification. Upon detecting the first reference signal having the first transmit beam characteristic from the BS 105, the UE 115 determines a signal measurement (e.g., RSRQ or RSRP) for the first reference signal.

At action 660, the UE 115 determines whether the signal measurement for the first reference signal having the first transmit beam characteristic of the BS 105 received based on the first receive beam characteristic of the UE 115 satisfies a signal threshold. For example, the UE 115 determines that the signal measurement for the first reference signal satisfies the signal threshold.

At action 670, the UE 115 transmits a beam failure recovery request indicating the first transmit beam characteristic to the BS 105. The beam failure recovery request indicates to the BS 105 that the UE 115 desires to switch to communicate with the BS 105 using the selected first transmit beam characteristic. In some aspects, the indication of the first transmit beam characteristic may be in the form of a beam index or an SSB index.

At action 680, after transmitting the beam failure recovery request, the UE 115 monitors for a beam failure recovery based on the selected receive beam characteristic.

At action 690, upon the BS 105 detecting the beam failure recovery request, the BS 105 transmits a beam failure recovery response to the UE 115.

In some aspects, the beam failure recovery request may be random access request and the beam failure recovery response may be a random access response. The beam failure recovery request may be a random access preamble (e.g., a physical waveform sequence) . In some instances, the BS 105 may indicate a resource for transmitting a beam failure request for requesting the BS to use the first transmit beam characteristic for communication. Accordingly, the UE 115 may transmit the beam failure recovery request in the indicated resource. In some instances, the beam failure recovery response may include a schedule or an UL grant for the UE 115 to transmit an UL communication. The inclusion of the scheduling grant in the beam recovery response may indicate that the beam failure recovery is successful and the beam failure recovery procedure may end. After completing the beam failure recovery successfully, the BS 105 and the UE 115 may communicate with each other based on the first transmit beam characteristic of the BS 105 and the first receive beam characteristic of the UE 115.

As can be observed, since the UE 115 selects the first transmit-receive beam pair selection directly from the stored record rather than performing a beam pair candidate identification or search as discussed above in the scheme 230 and/or the method 300 with reference FIGS. 2 and 3, respectively, the UE 115 may complete the beam failure recovery quickly, reducing the beam failure recovery response time significantly. If the ongoing communication at block 610 is a URLLC, the UE 115 and the BS 105 may resume the communication with a shorter interruption time. Accordingly, the URLLC performance may be improved or less impacted by a beam failure occurrence.

In some aspects, the record may include multiple transmit-receive beam pair selections that the UE 115 may use for a beam failure recovery in the first cell. For example, if the UE 115 determines that a signal measurement based on the first transmit-receive beam pair selection fails to satisfy the threshold for beam failure recovery or the UE 115 fails to receive beam failure recovery response form the BS 105 utilizing the first transmit-receive beam pair selection, the UE 115 may re-attempt to perform a beam failure recovery (e.g., repeating the signal measurement, beam failure recovery request transmission, and/or beam failure recovery response monitoring at

actions

650, 660, 670, and 680) based on a next preferred transmit-receive beam pair selection from the record.

FIG. 7 is a block diagram of an exemplary BS 700 according to some aspects of the present disclosure. The BS 700 may be a BS 105 in the network 100 as discussed above in FIG. 1. As shown, the BS 700 may include a processor 702, a memory 704, a beam module 708, a communication module 709, a transceiver 710 including a modem subsystem 712 and a RF unit 714, and one or more antennas 716. These elements may be in direct or indirect communication with each other, for example via one or more buses.

The processor 702 may have various features as a specific-type processor. For example, these may include a CPU, a DSP, an ASIC, a controller, a FPGA device, another hardware device, a firmware device, or any combination thereof configured to perform the operations described herein. The processor 702 may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

The memory 704 may include a cache memory (e.g., a cache memory of the processor 702) , RAM, MRAM, ROM, PROM, EPROM, EEPROM, flash memory, a solid state memory device, one or more hard disk drives, memristor-based arrays, other forms of volatile and non-volatile memory, or a combination of different types of memory. In some aspects, the memory 704 may include a non-transitory computer-readable medium. The memory 704 may store instructions 706. The instructions 706 may include instructions that, when executed by the processor 702, cause the processor 702 to perform operations described herein, for example, aspects of FIGS. 2A-2B, 3, 4, 5, and 6. Instructions 706 may also be referred to as program code. The program code may be for causing a wireless communication device to perform these operations, for example by causing one or more processors (such as processor 702) to control or command the wireless communication device to do so. The terms “instructions” and “code” should be interpreted broadly to include any type of computer-readable statement (s) . For example, the terms “instructions” and “code” may refer to one or more programs, routines, sub-routines, functions, procedures, etc. “Instructions” and “code” may include a single computer-readable statement or many computer-readable statements.

The beam module 708 and/or the communication module 709 may be implemented via hardware, software, or combinations thereof. For example, the beam module 708 and/or the communication module 709 may be implemented as a processor, circuit, and/or instructions 706 stored in the memory 704 and executed by the processor 702. In some instances, the beam module 708 and/or the communication module 709 can be integrated within the modem subsystem 712. For example, the beam module 708 and/or the communication module 709 can be implemented by a combination of software components (e.g., executed by a DSP or a general processor) and hardware components (e.g., logic gates and circuitry) within the modem subsystem 712.

The beam module 708 and/or the communication module 709 may coordinate with various components (e.g., the processor 702, the memory 704, and/or the transceiver 710) of the BS 700 to perform various aspects of the present disclosure, for example, aspects of 2A-2B, 3, 4, 5, and 6. In some aspects, the beam module 708 is configured to determine a set of transmit beam characteristics to be used for communications with UEs (e.g., the UEs 115) , configure the transceiver 710 and/or the antennas 716 to sweep across the set of transmit beam characteristics for beam reference signals (e.g., SSBs and/or CSI-RSs) transmissions, track and maintain a best transmit beam and/or a best receive beam for communications with each UE or each groups of UEs, and/or perform beam failure recovery with UEs (e.g., by receiving beam failure recovery requests and/or transmitting beam failure recovery response) .

The communication module 709 is configured to transmit beam reference signals (e.g., SSBs and/or CSI-RSs) to facilitate beam measurements at UE, transmit SSBs to facilitate initial network access, establish a connection (e.g., an RRC connection) with UEs, and/or communicate data (e.g., URLLC data) with UEs.

As shown, the transceiver 710 may include the modem subsystem 712 and the RF unit 714. The transceiver 710 can be configured to communicate bi-directionally with other devices, such as the UEs 115 and/or another core network element. The modem subsystem 712 may be configured to modulate and/or encode data according to a MCS, e.g., a LDPC coding scheme, a turbo coding scheme, a convolutional coding scheme, a digital beamforming scheme, etc. The RF unit 714 may be configured to process (e.g., perform analog to digital conversion or digital to analog conversion, etc. ) modulated/encoded data (e.g., SSBs, CSI-RSs, beam failure recovery responses, scheduling grants, DL data, DL URLLC data) from the modem subsystem 712 (on outbound transmissions) or of transmissions originating from another source such as a UE 115. The RF unit 714 may be further configured to perform analog beamforming in conjunction with the digital beamforming. Although shown as integrated together in transceiver 710, the modem subsystem 712 and/or the RF unit 714 may be separate devices that are coupled together at the BS 105 to enable the BS 105 to communicate with other devices.

The RF unit 714 may provide the modulated and/or processed data, e.g. data packets (or, more generally, data messages that may contain one or more data packets and other information) , to the antennas 716 for transmission to one or more other devices. This may include, for example, transmission of information to complete attachment to a network and communication with a camped UE 115 according to some aspects of the present disclosure. The antennas 716 may further receive data messages transmitted from other devices and provide the received data messages for processing and/or demodulation at the transceiver 710. The transceiver 710 may provide the demodulated and decoded data (e.g., beam failure recovery requests, UL data, UL URLLC data) to the beam module 708 and/or the communication module 709 for processing. The antennas 716 may include multiple antennas of similar or different designs in order to sustain multiple transmission links.

In an aspect, the BS 700 can include multiple transceivers 710 implementing different RATs (e.g., NR and LTE) . In an aspect, the BS 700 can include a single transceiver 710 implementing multiple RATs (e.g., NR and LTE) . In an aspect, the transceiver 710 can include various components, where different combinations of components can implement different RATs.

FIG. 8 is a block diagram of an exemplary UE 800 according to some aspects of the present disclosure. The UE 800 may be a UE 115 as discussed above with respect to FIG. 1. As shown, the UE 800 may include a processor 802, a memory 804, a sensor module 807, a beam module 808, a communication module 809, a transceiver 810 including a modem subsystem 812 and a radio frequency (RF) unit 814, and one or more antennas 816. These elements may be in direct or indirect communication with each other, for example via one or more buses.

The processor 802 may include a central processing unit (CPU) , a digital signal processor (DSP) , an application specific integrated circuit (ASIC) , a controller, a field programmable gate array (FPGA) device, another hardware device, a firmware device, or any combination thereof configured to perform the operations described herein. The processor 802 may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

The memory 804 may include a cache memory (e.g., a cache memory of the processor 802) , random access memory (RAM) , magnetoresistive RAM (MRAM) , read-only memory (ROM) , programmable read-only memory (PROM) , erasable programmable read only memory (EPROM) , electrically erasable programmable read only memory (EEPROM) , flash memory, solid state memory device, hard disk drives, other forms of volatile and non-volatile memory, or a combination of different types of memory. In an aspect, the memory 804 includes a non-transitory computer-readable medium. The memory 804 may store, or have recorded thereon, instructions 806. The instructions 806 may include instructions that, when executed by the processor 802, cause the processor 802 to perform the operations described herein with reference to the UEs 115 in connection with aspects of the present disclosure, for example, aspects of FIGS. 2A-2B, 3, 4, 5, 6, and 9. Instructions 806 may also be referred to as program code, which may be interpreted broadly to include any type of computer-readable statement (s) as discussed above with respect to FIG. 7.

The sensor module 807, the beam module 808, and/or the communication module 809 may be implemented via hardware, software, or combinations thereof. For example, the sensor module 807, the beam module 808, and/or the communication module 809 may be implemented as a processor, circuit, and/or instructions 806 stored in the memory 804 and executed by the processor 802. In some instances, the sensor module 807, the beam module 808, and/or the communication module 809 can be integrated within the modem subsystem 812. For example, the sensor module 807, the beam module 808, and/or the communication module 809 can be implemented by a combination of software components (e.g., executed by a DSP or a general processor) and hardware components (e.g., logic gates and circuitry) within the modem subsystem 712.

The sensor module 807, the beam module 808, and/or the communication module 809 may coordinate with various components (e.g., the processor 802, the memory 804, and/or the transceiver 810) of the UE 800 to perform various aspects of the present disclosure, for example, aspects of 2A-2B, 3, 4, 5, 6, and 9. In some aspects, the sensor module 807 may include various sensors, such as radar, lidar, and/or GPSs configured to generate sensor information related to geographical location (e.g., a geographical coordinate) and/or an orientation (e.g., with respect to a reference coordinate system in space) of the UE 800.

In some aspects, the beam module 808 is configured to record a plurality of transmit-receive beam pair selections in one or more cells frequently visited by the UE 800, store or cache the record and associated cell information in the memory 804, detect a beam failure event, perform a beam failure recovery procedure by utilizing the stored transmit-receive beam pair selections. To perform the beam failure recovery, the beam module 808 is further configured to select a first transmit-receive beam pair selection from the plurality of transmit-receive beam pair selections, perform a beam measurement based on the selected first transmit-receive beam pair selection, and determine whether beam measurement (e.g., RSRP or RSRQ) based on the first transmit-receive beam pair selection satisfies a signal threshold, and utilize the selected transmit-receive beam pair to continue with the beam failure recovery procedure if the beam measurement satisfies the signal threshold, for example, as discussed above in relation to FIG. 6.

In some aspects, the beam module 808 is configured to determine the transmit-receive beam pair selections in one or more cells frequently visited by the UE 800, for example, by monitoring for beam reference signals from a BS (e.g., the BSs 105 and/or 700) , perform signal measurements by configuring its transceiver 810 and/or antennas 816 to sweep across a set of predefined receive beam characteristics. The beam module 808 is further configured to generate the record of the determined transmit-receive beam pair selections, and update the record, for example, as discussed above in relation to FIGS. 3, 4, and 5.

The communication module 809 is configured to perform an initial network access, establish a connection (e.g., an RRC connection) with a BS (e.g., the BSs 105 and/or 700) , and communicate data (e.g., UL URLLC data and/or DL URLLC data) with the BS.

As shown, the transceiver 810 may include the modem subsystem 812 and the RF unit 814. The transceiver 810 can be configured to communicate bi-directionally with other devices, such as the BSs 105. The modem subsystem 812 may be configured to modulate and/or encode the data from the memory 804, the beam module 808, and/or the communication module 809 according to a modulation and coding scheme (MCS) , e.g., a low-density parity check (LDPC) coding scheme, a turbo coding scheme, a convolutional coding scheme, a digital beamforming scheme, etc. The RF unit 814 may be configured to process (e.g., perform analog to digital conversion or digital to analog conversion, etc. ) modulated/encoded data (e.g., beam measurement reports, beam failure recovery request, UL data, and/or UL URLLC data) from the modem subsystem 812 (on outbound transmissions) or of transmissions originating from another source such as a UE 115 or a BS 105. The RF unit 814 may be further configured to perform analog beamforming in conjunction with the digital beamforming. Although shown as integrated together in transceiver 810, the modem subsystem 812 and the RF unit 814 may be separate devices that are coupled together at the UE 115 to enable the UE 115 to communicate with other devices.

The RF unit 814 may provide the modulated and/or processed data, e.g. data packets (or, more generally, data messages that may include one or more data packets and other information) , to the antennas 816 for transmission to one or more other devices. The antennas 816 may further receive data messages transmitted from other devices. The antennas 816 may provide the received data messages for processing and/or demodulation at the transceiver 810. The transceiver 810 may provide the demodulated and decoded data (e.g., SSBs, CSI-RSs, beam reference signals, DL data, DL URLLC data, beam failure recovery response) to the beam module 808 and/or the communication module 809 for processing. The antennas 816 may include multiple antennas of similar or different designs in order to sustain multiple transmission links. The RF unit 814 may configure the antennas 816.

In some aspects, the processor 802 is configured to coordinate with components of the UE 800 to store, at the memory 804, a record of a plurality of transmit-receive beam pair selections in one or more cells and associated cell information, detect a beam failure, and perform, in response to the beam failure, a beam failure recovery according to the stored record.

In an aspect, the UE 800 can include multiple transceivers 810 implementing different RATs (e.g., NR and LTE) . In an aspect, the UE 800 can include a single transceiver 810 implementing multiple RATs (e.g., NR and LTE) . In an aspect, the transceiver 810 can include various components, where different combinations of components can implement different RATs.

FIG. 9 is a flow diagram of a wireless communication method 900 according to some aspects of the present disclosure. Aspects of the method 900 can be executed by a computing device (e.g., a processor, processing circuit, and/or other suitable component) of a wireless communication device or other suitable means for performing the steps. For example, a wireless communication device, such as a UE 115 and 800, may utilize one or more components, such as the processor 802, the memory 804, the sensor module 807, the beam module 808, the communication module 809, the transceiver 810, the modem 812, and/or the one or more antennas 816, to execute the steps of method 900. The method 900 may employ similar mechanisms as described above in FIGS. 2A, 2B, 4, 5, and/or 6. As illustrated, the method 900 includes a number of enumerated steps, but aspects of the method 900 may include additional steps before, after, and in between the enumerated steps. In some aspects, one or more of the enumerated steps may be omitted or performed in a different order.

At block 910, a UE (e.g., the UE 115 and/or 800) stores, at a memory of the UE, a record of a plurality of transmit-receive beam pair selections in one or more cells and associated cell information. In some aspects, each transmit-receive beam pair selection of the plurality of transmit-receive beam pair selection may include a transmit beam characteristic of a BS in a corresponding cell and a receive beam characteristic of the UE. The record may be generated using the method 400 and/or the scheme 500 discussed above with reference to FIGS. 4 and 5, respectively. In some instances, the UE may utilize one or more components, such as the processor 802, to store the record of the plurality of transmit-receive beam pair selections and associated cell information at the memory, such as the memory 804.

At block 920, the UE detects a beam failure. In some instances, the UE may detect the beam failure based on a signal measurement (e.g., an SSB measurement) , a failed SSB detection, and/or a higher error rate for an ongoing communication. In some instances, the UE may utilize one or more components, such as the processor 802, the memory 804, the sensor module 807, the beam module 808, the communication module 809, the transceiver 810, the modem 812, and/or the one or more antennas 816, to detect the beam failure.

At block 930, the UE performs, in response to the beam failure, a beam failure recovery according to the stored record. In some instances, the UE may utilize one or more components, such as the processor 802, the memory 804, the sensor module 807, the beam module 808, the communication module 809, the transceiver 810, the modem 812, and/or the one or more antennas 816, to perform the beam failure recovery according to the stored record.

In some aspects, as part of detecting the beam failure at block 920, the UE 115 may detect the beam failure in a first cell of the one or more cells, and as part of performing the beam failure recovery at block 930, the UE may select a first transmit-receive beam pair selection from the plurality of transmit-receive beam pair selections based on the first transmit-receive beam pair selection being associated with the first cell.

In some aspects, the UE may further receive, from at least one of a sensor at the UE, position information of the UE, and as part of detecting the beam failure at block 920, the UE may determine the UE is within the first cell based on the received position information. In some aspects, the associated cell information stored at the memory may include at least one of a cell ID or a PLMN parameter (e.g., a PLMN ID) associated with the first transmit-receive beam pair selection, and as part of performing the beam failure recovery at block 930, the UE may select the first transmit-receive beam pair selection further based on at least one of a cell ID of the first cell being the same as the cell ID associated with the first transmit-receive beam pair selection or a PLMN parameter of the first cell being the same as the PLMN parameter associated with the first transmit-receive beam pair selection.

In some aspects, the record may include position information of the UE associated with the first transmit-receive beam pair selection, and as part of performing the beam failure recovery at block 930, the UE may select the first transmit-receive beam pair selection further based on a comparison of at least one of geographical information or orientation information of the UE when the beam failure is detected and the position information of the UE associated with the first transmit-receive beam pair selection. In some aspects, the UE may further receive, from a sensor at the UE, the at least one of the geographical information or the orientation information of the UE when the beam failure is detected. In some aspects, as part of performing the beam failure recovery at block 930, the UE may identify a second transmit-receive beam pair selection of the plurality of transmit-receive beam pair selections associated with the first cell and select the first transmit-receive beam pair selection further based on the first transmit-receive beam pair selection having a higher preference than the second transmit-receive beam pair selection.

In some aspects, the first transmit-receive beam pair selection includes a first transmit beam characteristic (e.g., a transmit beam direction) of a BS in the first cell and a first receive beam characteristic (e.g., a receive beam direction) of the UE. In some aspects, as part of performing the beam failure recovery at block 930, the UE may perform a beam measurement based on the first transmit beam characteristic of the BS and the first receive beam characteristic of the UE indicated by the first transmit-receive beam pair selection, transmit, to the BS, a beam failure recovery request indicating the first transmit beam characteristic of the BS based on the beam measurement satisfying a threshold, and monitor, based on the first receive beam characteristic, for a beam failure recovery response from the BS.

Information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

The various illustrative blocks and modules described in connection with the disclosure herein may be implemented or performed with a general-purpose processor, a DSP, an ASIC, an FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration) .

The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Other examples and implementations are within the scope of the disclosure and appended claims. For example, due to the nature of software, functions described above can be implemented using software executed by a processor, hardware, firmware, hardwiring, or combinations of any of these. Features implementing functions may also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations. Also, as used herein, including in the claims, “or” as used in a list of items (for example, a list of items prefaced by a phrase such as “at least one of” or “one or more of” ) indicates an inclusive list such that, for example, a list of [at least one of A, B, or C] means A or B or C or AB or AC or BC or ABC (i.e., A and B and C) .

As those of some skill in this art will by now appreciate and depending on the particular application at hand, many modifications, substitutions and variations can be made in and to the materials, apparatus, configurations and methods of use of the devices of the present disclosure without departing from the spirit and scope thereof. In light of this, the scope of the present disclosure should not be limited to that of the particular embodiments illustrated and described herein, as they are merely by way of some examples thereof, but rather, should be fully commensurate with that of the claims appended hereafter and their functional equivalents.

Claims

A method of wireless communication performed by a user equipment (UE) , the method comprising:

storing, at a memory of the UE, a record of a plurality of transmit-receive beam pair selections in one or more cells and associated cell information;

detecting a beam failure; and

performing, in response to the beam failure, a beam failure recovery according to the stored record.
The method of claim 1, wherein:

the detecting the beam failure comprises:

detecting the beam failure in a first cell of the one or more cells, and

the performing the beam failure recovery comprises:

selecting a first transmit-receive beam pair selection from the plurality of transmit-receive beam pair selections based on the first transmit-receive beam pair selection being associated with the first cell.
The method of claim 2, further comprising:

receiving, from a sensor at the UE, position information of the UE,

wherein the detecting the beam failure further comprises:

determining the UE is within the first cell based on the received position information.
The method of claim 2, wherein the associated cell information includes at least one of a cell identifier (ID) or a public land mobile network (PLMN) parameter associated with the first transmit-receive beam pair selection, and wherein the performing the beam failure recovery further comprises:

selecting the first transmit-receive beam pair selection further based on at least one of a cell ID of the first cell being the same as the cell ID associated with the first transmit-receive beam pair selection or a PLMN parameter of the first cell being the same as the PLMN parameter associated with the first transmit-receive beam pair selection.
The method of claim 2, wherein the record includes position information of the UE associated with the first transmit-receive beam pair selection, and wherein the performing the beam failure recovery further comprises:

selecting the first transmit-receive beam pair selection further based on a comparison of at least one of a geographical location information or orientation information of the UE when the beam failure is detected and the position information of the UE associated with the first transmit-receive beam pair selection.
The method of claim 5, further comprising:

receiving, from a sensor at the UE, the at least one of the geographical location information or the orientation information of the UE when the beam failure is detected.
The method of claim 2, wherein the performing the beam failure recovery further comprises:

identifying a second transmit-receive beam pair selection of the plurality of transmit-receive beam pair selections associated with the first cell; and

selecting the first transmit-receive beam pair selection further based on the first transmit-receive beam pair selection having a higher preference than the second transmit-receive beam pair selection.
The method of claim 2, wherein the first transmit-receive beam pair selection includes a first transmit beam characteristic of a base station (BS) in the first cell and a first receive beam characteristic of the UE.
The method of claim 8, wherein the first transmit-receive beam pair selection includes a transmit beam direction of the BS and a receive beam direction of the UE.
The method of claim 8, wherein the performing the beam failure recovery comprises:

performing a beam measurement based on the first transmit beam characteristic of the BS and the first receive beam characteristic of the UE indicated by the first transmit-receive beam pair selection; and

transmitting, to the BS, a beam failure recovery request indicating the first transmit beam characteristic of the BS based on the beam measurement.
The method of claim 10, wherein the performing the beam failure recovery comprises:

performing the beam measurement by:

receiving, from the BS based on the first receive beam characteristic, a reference signal having the first transmit beam characteristic; and

determining a signal measurement for the reference signal based on the first receive beam characteristic; and

transmitting, to the BS, the beam failure recovery request indicating the first transmit beam characteristic further based on the signal measurement satisfying a threshold.
The method of claim 11, wherein the signal measurement for the reference signal includes a reference signal received power (RSRP) measurement.
The method of claim 11, further comprising:

monitoring, based on the first receive beam characteristic, for a beam failure recovery response from the BS.
The method of claim 1, further comprising:

generating, before the beam failure, the record of the plurality of transmit-receive beam pair selections.
The method of claim 14, further comprising:

determining a first transmit-receive beam pair selection of the plurality of transmit-receive beam pair selections by:

receiving, from a base station (BS) in a first cell of the one or more cells, a first reference signal based on a first receive beam characteristic of the UE, the first reference signal having a first transmit beam characteristic of the BS;

receiving, from the BS, a second reference signal based on a second receive beam characteristic of the UE, the second reference signal having a second transmit beam characteristic of the BS; and

selecting the first transmit beam characteristic and the first receive beam characteristic based on a signal measurement of the first reference signal being greater than a signal measurement of the second reference signal and satisfying a threshold,

wherein the generating the record comprises:

adding the first transmit-receive beam pair selection including the first transmit beam characteristic and the second transmit beam characteristic to the record.
The method of claim 15, wherein the determining a first transmit-receive beam pair selection further comprises:

receiving, from the BS, the first reference signal including a synchronization signal block (SSB) having the first transmit beam characteristic; and

receiving, from the BS, the second reference signal including a SSB having the second transmit beam characteristic.
The method of claim 15, wherein the generating the record further comprises:

adding the first transmit-receive beam pair selection to the record further based on a cell identifier (ID) of the first cell being the same as a cell ID associated with a second transmit-receive beam pair selection of the plurality of transmit-receive beam pair selections.
The method of claim 15, wherein the determining the first transmit-receive beam pair selection is based on a previous beam failure in the first cell.
The method of claim 15, wherein the determining the first transmit-receive beam pair selection is based on a cell reselection.
The method of claim 15, wherein the determining the first transmit-receive beam pair selection is based on a distance travelled by the UE.
The method of claim 15, wherein the determining the first transmit-receive beam pair selection is based on an update cycle.
The method of claim 1, wherein the storing the record of the plurality of the transmit-receive beam pair selections in the one or more cells and the associated cell information in the memory is based on the one or more cells being visited by the UE more frequently than another cell over a time period.
A user equipment (UE) comprising:

a memory; and

a processor configured to:

store, at the memory, a record of a plurality of transmit-receive beam pair selections in one or more cells and associated cell information;

detect a beam failure; and

perform, in response to the beam failure, a beam failure recovery according to the stored record.
The UE of claim 23, wherein:

the processor configured to detect the beam failure is configured to:

detect the beam failure in a first cell of the one or more cells, and

the processor configured to perform the beam failure recovery is configured to:

select a first transmit-receive beam pair selection from the plurality of transmit-receive beam pair selections based on the first transmit-receive beam pair selection being associated with the first cell.
The UE of claim 24, further comprising:

a sensor; and

a transceiver configured to:

receive, from the sensor, position information of the UE,

wherein the processor configured to detect the beam failure is configured to:

determine the UE is within the first cell based on the received position information.
The UE of claim 24, wherein the associated cell information includes at least one of a cell identifier (ID) or a public land mobile network (PLMN) parameter associated with the first transmit-receive beam pair selection, and wherein the processor configured to perform the beam failure recovery is further configured to:

select the first transmit-receive beam pair selection further based on at least one of a cell ID of the first cell being the same as the cell ID associated with the first transmit-receive beam pair selection or a PLMN parameter of the first cell being the same as the PLMN parameter associated with the first transmit-receive beam pair selection.
The UE of claim 24, wherein the record includes position information of the UE associated with the first transmit-receive beam pair selection, and wherein the processor configured to perform the beam failure recovery is further configured to:

select the first transmit-receive beam pair selection further based on a comparison of at least one of a geographical location information or orientation information of the UE when the beam failure is detected and the position information of the UE associated with the first transmit-receive beam pair selection.
The UE of claim 27, further comprising:

a sensor; and

a transceiver configured to:

receive, from the sensor, the at least one of the geographical location information or the orientation information of the UE when the beam failure is detected.
The UE of claim 24, wherein the processor configured to perform the beam failure recovery is further configured to:

identify a second transmit-receive beam pair selection of the plurality of transmit-receive beam pair selections associated with the first cell; and

select the first transmit-receive beam pair selection further based on the first transmit-receive beam pair selection having a higher preference than the second transmit-receive beam pair selection.
The UE of claim 24, wherein the first transmit-receive beam pair selection includes a first transmit beam characteristic of a base station (BS) in the first cell and a first receive beam characteristic of the UE.
The UE of claim 30, wherein the first transmit-receive beam pair selection includes a transmit beam direction of the BS and a receive beam direction of the UE.
The UE of claim 30, wherein:

the processor configured to perform the beam failure recovery is configured to:

perform a beam measurement based on the first transmit beam characteristic of the BS and the first receive beam characteristic of the UE indicated by the first transmit-receive beam pair selection,

the UE further comprises:

a transceiver configured to:

transmit, to the BS, a beam failure recovery request indicating the first transmit beam characteristic of the BS based on the beam measurement.
The UE of claim 32, wherein:

the processor configured to perform the beam failure recovery is configured to:

perform the beam measurement by:

receiving, from the BS based on the first receive beam characteristic, a reference signal having the first transmit beam characteristic; and

determining a signal measurement for the reference signal based on the first receive beam characteristic, and

the transceiver configured to transmit the beam failure recovery request is configured to:

transmit, to the BS, the beam failure recovery request indicating the first transmit beam characteristic further based on the signal measurement satisfying a threshold.
The UE of claim 33, wherein the signal measurement for the reference signal includes a reference signal received power (RSRP) measurement.
The UE of claim 33, wherein the processor is further configured to:

monitor, based on the first receive beam characteristic, for a beam failure recovery response from the BS.
The UE of claim 23, wherein the processor is further configured to:

generate, before the beam failure, the record of the plurality of transmit-receive beam pair selections.
The UE of claim 36, further comprising:

a transceiver configured to:

receive, from a base station (BS) in a first cell of the one or more cells, a first reference signal based on a first receive beam characteristic of the UE, the first reference signal having a first transmit beam characteristic of the BS; and

receive, from the BS, a second reference signal based on a second receive beam characteristic of the UE, the second reference signal having a second transmit beam characteristic of the BS,

wherein the processor is further configured to:

determine a first transmit-receive beam pair selection of the plurality of transmit-receive beam pair selections by selecting the first transmit beam characteristic and the first receive beam characteristic based on a signal measurement of the first reference signal being greater than a signal measurement of the second reference signal and satisfying a threshold, and

wherein the processor configured to generate the record is configured to:

add the first transmit-receive beam pair selection including the first transmit beam characteristic and the second transmit beam characteristic to the record.
The UE of claim 37, wherein:

the transceiver configured to receive the first reference signal is configured to:

receive, from the BS, the first reference signal including a synchronization signal block (SSB) having the first transmit beam characteristic, and

the transceiver configured to receive the second reference signal is configured to:

receive, from the BS, the second reference signal including a SSB having the second transmit beam characteristic.
The UE of claim 37, wherein the processor configured to generate the record is further configured to:

add the first transmit-receive beam pair selection to the record further based on a cell identifier (ID) of the first cell being the same as a cell ID associated with a second transmit-receive beam pair selection of the plurality of transmit-receive beam pair selections.
The UE of claim 37, wherein the processor configured to determine the first transmit-receive beam pair selection is configured to:

determine the first transmit-receive beam pair selection based on a previous beam failure in the first cell.
The UE of claim 37, wherein the processor configured to determine the first transmit-receive beam pair selection is configured to:

determine the first transmit-receive beam pair selection based on a cell reselection.
The UE of claim 37, wherein the processor configured to determine the first transmit-receive beam pair selection is configured to:

determine the first transmit-receive beam pair selection based on a distance travelled by the UE.
The UE of claim 37, wherein the processor configured to determine the first transmit-receive beam pair selection is configured to:

determine the first transmit-receive beam pair selection based on an update cycle.
The UE of claim 23, wherein the processor configured to store the record of the plurality of the transmit-receive beam pair selections in the one or more cells and the associated cell information in the memory is configured to:

store the record of the plurality of the transmit-receive beam pair selections in the one or more cells and the associated cell information in the memory based on the one or more cells being visited by the UE more frequently than another cell over a time period.
A non-transitory computer-readable medium having program code recorded thereon, the program code comprising:

code for causing a user equipment (UE) to store, at a memory of the UE, a record of a plurality of transmit-receive beam pair selections in one or more cells and associated cell information;

code for causing the UE to detect a beam failure; and

code for causing the UE to perform, in response to the beam failure, a beam failure recovery according to the stored record.
The non-transitory computer-readable medium of claim 45, wherein:

the code for causing the UE to detect the beam failure is configured to:

detect the beam failure in a first cell of the one or more cells, and

the code for causing the UE to perform the beam failure recovery is configured to:

select a first transmit-receive beam pair selection from the plurality of transmit-receive beam pair selections based on the first transmit-receive beam pair selection being associated with the first cell.
The non-transitory computer-readable medium of claim 46, further comprising:

code for causing the UE to receive, from a sensor at the UE, position information of the UE,

wherein the code for causing the UE to detect the beam failure is configured to:

determine the UE is within the first cell based on the received position information.
The non-transitory computer-readable medium of claim 46, wherein the associated cell information includes at least one of a cell identifier (ID) or a public land mobile network (PLMN) parameter associated with the first transmit-receive beam pair selection, and wherein the code for causing the UE to perform the beam failure recovery is further configured to:

select the first transmit-receive beam pair selection further based on at least one of a cell ID of the first cell being the same as the cell ID associated with the first transmit-receive beam pair selection or a PLMN parameter of the first cell being the same as the PLMN parameter associated with the first transmit-receive beam pair selection.
The non-transitory computer-readable medium of claim 46, wherein the record includes position information of the UE associated with the first transmit-receive beam pair selection, and wherein the code for causing the UE to perform the beam failure recovery is further configured to:

select the first transmit-receive beam pair selection further based on a comparison of at least one of a geographical location information or orientation information of the UE when the beam failure is detected and the position information of the UE associated with the first transmit-receive beam pair selection.
The non-transitory computer-readable medium of claim 49, further comprising:

code for causing the UE to receive, from a sensor at the UE, the at least one of the geographical location information or the orientation information of the UE when the beam failure is detected.
The non-transitory computer-readable medium of claim 46, wherein the code for causing the UE to perform the beam failure recovery is further configured to:

identify a second transmit-receive beam pair selection of the plurality of transmit-receive beam pair selections associated with the first cell; and

select the first transmit-receive beam pair selection further based on the first transmit-receive beam pair selection having a higher preference than the second transmit-receive beam pair selection.
The non-transitory computer-readable medium of claim 46, wherein the first transmit-receive beam pair selection includes a first transmit beam characteristic of a base station (BS) in the first cell and a first receive beam characteristic of the UE.
The non-transitory computer-readable medium of claim 52, wherein the first transmit-receive beam pair selection includes a transmit beam direction of the BS and a receive beam direction of the UE.
The non-transitory computer-readable medium of claim 52, wherein:

the code for causing the UE to perform the beam failure recovery is configured to:

perform a beam measurement based on the first transmit beam characteristic of the BS and the first receive beam characteristic of the UE indicated by the first transmit-receive beam pair selection,

the non-transitory computer-readable medium further comprises:

code for causing the UE to transmit, to the BS, a beam failure recovery request indicating the first transmit beam characteristic of the BS based on the beam measurement.
The non-transitory computer-readable medium of claim 54, wherein:

the code for causing the UE to perform the beam failure recovery is configured to:

perform the beam measurement by:

receiving, from the BS based on the first receive beam characteristic, a reference signal having the first transmit beam characteristic; and

determining a signal measurement for the reference signal based on the first receive beam characteristic, and

the code for causing the UE to transmit the beam failure recovery request is configured to:

transmit, to the BS, the beam failure recovery request indicating the first transmit beam characteristic further based on the signal measurement satisfying a threshold.
The non-transitory computer-readable medium of claim 55, wherein the signal measurement for the reference signal includes a reference signal received power (RSRP) measurement.
The non-transitory computer-readable medium of claim 55, further comprising:

code for causing the UE to monitor, based on the first receive beam characteristic, for a beam failure recovery response from the BS.
The non-transitory computer-readable medium of claim 45, further comprising:

code for causing the UE to generate, before the beam failure, the record of the plurality of transmit-receive beam pair selections.
The non-transitory computer-readable medium of claim 58, further comprising:

code for causing the UE to determine a first transmit-receive beam pair selection of the plurality of transmit-receive beam pair selections by:

receiving, from a base station (BS) in a first cell of the one or more cells, a first reference signal based on a first receive beam characteristic of the UE, the first reference signal having a first transmit beam characteristic of the BS;

receiving, from the BS, a second reference signal based on a second receive beam characteristic of the UE, the second reference signal having a second transmit beam characteristic of the BS; and

selecting the first transmit beam characteristic and the first receive beam characteristic based on a signal measurement of the first reference signal being greater than a signal measurement of the second reference signal and satisfying a threshold,

wherein the code for causing the UE to generate the record is configured to:

add the first transmit-receive beam pair selection including the first transmit beam characteristic and the second transmit beam characteristic to the record.
The non-transitory computer-readable medium of claim 59, wherein the code for causing the UE to determine the first transmit-receive beam pair selection is configured to:

receive, from the BS, the first reference signal including a synchronization signal block (SSB) having the first transmit beam characteristic; and

receive, from the BS, the second reference signal including a SSB having the second transmit beam characteristic.
The non-transitory computer-readable medium of claim 59, wherein the code for causing the UE to generate the record is further configured to:

add the first transmit-receive beam pair selection to the record further based on a cell identifier (ID) of the first cell being the same as a cell ID associated with a second transmit-receive beam pair selection of the plurality of transmit-receive beam pair selections.
The non-transitory computer-readable medium of claim 59, wherein the code for causing the UE to determine the first transmit-receive beam pair selection is configured to:

determine the first transmit-receive beam pair selection based on a previous beam failure in the first cell.
The non-transitory computer-readable medium of claim 59, wherein the code for causing the UE to determine the first transmit-receive beam pair selection is configured to:

determine the first transmit-receive beam pair selection based on a cell reselection.
The non-transitory computer-readable medium of claim 59, wherein the code for causing the UE to determine the first transmit-receive beam pair selection is configured to:

determine the first transmit-receive beam pair selection based on a distance travelled by the UE.
The non-transitory computer-readable medium of claim 59, wherein the code for causing the UE to determine the first transmit-receive beam pair selection is configured to:

determine the first transmit-receive beam pair selection based on an update cycle.
The non-transitory computer-readable medium of claim 45, wherein the code for causing the UE to store the record of the plurality of the transmit-receive beam pair selections in the one or more cells and the associated cell information in the memory is configured to:

store the record of the plurality of the transmit-receive beam pair selections in the one or more cells and the associated cell information in the memory based on the one or more cells being visited by the UE more frequently than another cell over a time period.
A user equipment (UE) comprising:

means for storing, at a memory of the UE, a record of a plurality of transmit-receive beam pair selections in one or more cells and associated cell information;

means for detecting a beam failure; and

means for performing, in response to the beam failure, a beam failure recovery according to the stored record.
The UE of claim 67, wherein:

the means for detecting the beam failure is configured to:

detect the beam failure in a first cell of the one or more cells, and

the means for performing the beam failure recovery is configured to:

select a first transmit-receive beam pair selection from the plurality of transmit-receive beam pair selections based on the first transmit-receive beam pair selection being associated with the first cell.
The UE of claim 68, further comprising:

means for receiving, from a sensor at the UE, position information of the UE,

wherein the means for detecting the beam failure is configured to:

determine the UE is within the first cell based on the received position information.
The UE of claim 68, wherein the associated cell information includes at least one of a cell identifier (ID) or a public land mobile network (PLMN) parameter associated with the first transmit-receive beam pair selection, and wherein the means for performing the beam failure recovery is further configured to:

select the first transmit-receive beam pair selection further based on at least one of a cell ID of the first cell being the same as the cell ID associated with the first transmit-receive beam pair selection or a PLMN parameter of the first cell being the same as the PLMN parameter associated with the first transmit-receive beam pair selection.
The UE of claim 68, wherein the record includes position information of the UE associated with the first transmit-receive beam pair selection, and wherein the means for performing the beam failure recovery is further configured to:

select the first transmit-receive beam pair selection further based on a comparison of at least one of a geographical location information or orientation information of the UE when the beam failure is detected and the position information of the UE associated with the first transmit-receive beam pair selection.
The UE of claim 71, further comprising:

means for receiving, from a sensor at the UE, the at least one of the geographical location information or the orientation information of the UE when the beam failure is detected.
The UE of claim 68, wherein the means for performing the beam failure recovery is further configured to:

identify a second transmit-receive beam pair selection of the plurality of transmit-receive beam pair selections associated with the first cell; and

select the first transmit-receive beam pair selection further based on the first transmit-receive beam pair selection having a higher preference than the second transmit-receive beam pair selection.
The UE of claim 68, wherein the first transmit-receive beam pair selection includes a first transmit beam characteristic of a base station (BS) in the first cell and a first receive beam characteristic of the UE.
The UE of claim 74, wherein the first transmit-receive beam pair selection includes a transmit beam direction of the BS and a receive beam direction of the UE.
The UE of claim 74, wherein:

the means for performing the beam failure recovery is configured to:

perform a beam measurement based on the first transmit beam characteristic of the BS and the first receive beam characteristic of the UE indicated by the first transmit-receive beam pair selection,

the UE further comprises:

means for transmitting, to the BS, a beam failure recovery request indicating the first transmit beam characteristic of the BS based on the beam measurement.
The UE of claim 76, wherein:

the means for performing the beam failure recovery is configured to:

perform the beam measurement by:

receiving, from the BS based on the first receive beam characteristic, a reference signal having the first transmit beam characteristic; and

determining a signal measurement for the reference signal based on the first receive beam characteristic, and

the means for transmitting the beam failure recovery request is configured to:

transmit, to the BS, the beam failure recovery request indicating the first transmit beam characteristic further based on the signal measurement satisfying a threshold.
The UE of claim 77, wherein the signal measurement for the reference signal includes a reference signal received power (RSRP) measurement.
The UE of claim 77, further comprising:

means for monitoring, based on the first receive beam characteristic, for a beam failure recovery response from the BS.
The UE of claim 67, further comprising:

means for generating, before the beam failure, the record of the plurality of transmit-receive beam pair selections.
The UE of claim 80, further comprising:

means for determining a first transmit-receive beam pair selection of the plurality of transmit-receive beam pair selections by:

receiving, from a base station (BS) in a first cell of the one or more cells, a first reference signal based on a first receive beam characteristic of the UE, the first reference signal having a first transmit beam characteristic of the BS;

receiving, from the BS, a second reference signal based on a second receive beam characteristic of the UE, the second reference signal having a second transmit beam characteristic of the BS; and

selecting the first transmit beam characteristic and the first receive beam characteristic based on a signal measurement of the first reference signal being greater than a signal measurement of the second reference signal and satisfying a threshold, wherein the means for generating the record is configured to:

add the first transmit-receive beam pair selection including the first transmit beam characteristic and the second transmit beam characteristic to the record.
The UE of claim 81, wherein means for determining the first transmit-receive beam pair selection is further configured to:

receive, from the BS, the first reference signal including a synchronization signal block (SSB) having the first transmit beam characteristic, and

receive, from the BS, the second reference signal including a SSB having the second transmit beam characteristic.
The UE of claim 81, wherein the means for generating the record is further configured to:

add the first transmit-receive beam pair selection to the record further based on a cell identifier (ID) of the first cell being the same as a cell ID associated with a second transmit-receive beam pair selection of the plurality of transmit-receive beam pair selections.
The UE of claim 81, wherein the means for determining the first transmit-receive beam pair selection is configured to:

determine the first transmit-receive beam pair selection based on a previous beam failure in the first cell.
The UE of claim 81, wherein the means for determining the first transmit-receive beam pair selection is configured to:

determine the first transmit-receive beam pair selection based on a cell reselection.
The UE of claim 81, wherein the means for determining the first transmit-receive beam pair selection is configured to:

determine the first transmit-receive beam pair selection based on a distance travelled by the UE.
The UE of claim 81, wherein the means for determining the first transmit-receive beam pair selection is configured to:

determine the first transmit-receive beam pair selection based on an update cycle.
The UE of claim 67, wherein the means for storing the record of the plurality of the transmit-receive beam pair selections in the one or more cells and the associated cell information in the memory is configured to:

store the record of the plurality of the transmit-receive beam pair selections in the one or more cells and the associated cell information in the memory based on the one or more cells being visited by the UE more frequently than another cell over a time period.